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1 
2 C and C++ XML Data Bindings {#mainpage}
3 ===========================
4 
5 [TOC]
6 
7 Introduction {#intro}
8 ============
9 
10 This article presents a detailed overview of the gSOAP XML data bindings for C
11 and C++. The XML data bindings for C and C++ are extensively used with gSOAP
12 Web services to serialize C and C++ data in XML as part of the SOAP/XML Web
13 services payloads. Also REST XML with gSOAP relies on XML serialization of C
14 and C++ data via XML data bindings.
15 
16 The major advantage of XML data bindings is that your application data is
17 always **type safe** in C and C++ by binding XML schema types to C/C++ types.
18 So integers in XML are bound to C integers, strings in XML are bound to C or
19 C++ strings, complex types in XML are bound to C structs or C++ classes, and so
20 on. The structured data you create and accept will fit the data model and is
21 **static type safe**. In other words, by leveraging strong typing in C/C++,
22 your XML data meets **XML schema validation requirements** and satisfies **XML
23 interoperability requirements**.
24 
25 In fact, gSOAP data bindings are more powerful than simply representing C/C++
26 data in XML. The gSOAP tools implement true and tested **structure-preserving
27 serialization** of C/C++ data in XML, including the serialization of cyclic
28 graph structures with id-ref XML attributes. The gSOAP tools also generate
29 routines for deep copying and deep deletion of C/C++ data structures to
30 simplify memory management. In addition, C/C++ structures are deserialized
31 into managed memory, managed by the gSOAP `soap` context.
32 
33 At the end of this article two examples are given to illustrate the application
34 of XML data bindings. The first simple example <i>`address.cpp`</i> shows how to use
35 wsdl2h to bind an XML schema to C++. The C++ application reads and writes an
36 XML file into and from a C++ "address book" data structure as a simple example.
37 The C++ data structure is a vector of address objects. The second example
38 <i>`graph.cpp`</i> shows how C++ data can be accurately serialized as a tree,
39 digraph, and cyclic graph in XML. The digraph and cyclic graph serialization
40 rules implement SOAP 1.1/1.2 multi-ref encoding with id-ref attributes to link
41 elements through IDREF XML references, creating a an XML graph with pointers to
42 XML nodes that preserves the structural integrity of the serialized C++ data.
43 
44 These examples demonstrate XML data bindings only for relatively simple data
45 structures and types. The gSOAP tools support more than just these type of
46 structures to serialize in XML. There are practically no limits to the
47 serialization of C and C++ data types in XML.
48 
49 Also the support for XML schema (XSD) components is unlimited. The wsdl2h tool
50 maps schemas to C and C++ using built-in intuitive mapping rules, while
51 allowing the mappings to be customized using a <i>`typemap.dat`</i> file with mapping
52 instructions for wsdl2h.
53 
54 The information in this article is applicable to gSOAP 2.8.26 and greater that
55 support C++11 features. However, C++11 is not required. The material and the
56 examples in this article use plain C and C++, until the point where we
57 introduce C++11 smart pointers and scoped enumerations. While most of the
58 examples in this article are given in C++, the concepts also apply to C with
59 the exception of containers, smart pointers, classes and their methods. None
60 of these exceptions limit the use of the gSOAP tools for C in any way.
61 
62 The data binding concepts described in this article were first envisioned in
63 1999 by Prof. Robert van Engelen at the Florida State University. An
64 implementation was created in 2000, named "stub/skeleton compiler". The first
65 articles on its successor version "gSOAP" appeared in 2002. The principle of
66 mapping XSD components to C/C++ types and vice versa is now widely adopted in
67 systems and programming languages, including Java web services and by C# WCF.
68 
69 We continue to be committed to our goal to empower C/C++ developers with
70 powerful autocoding tools for XML. Our commitment started in the very early
71 days of SOAP by actively participating in
72 [SOAP interoperability testing](http://www.whitemesa.com/interop.htm),
73 participating in the development and testing of the
74 [W3C XML Schema Patterns for Databinding Interoperability](http://www.w3.org/2002/ws/databinding),
75 and continues by contributing to the development of
76 [OASIS open standards](https://www.oasis-open.org) in partnership with leading
77 IT companies in the world.
78 
79 🔝 [Back to table of contents](#)
80 
81 Notational Conventions {#conventions}
82 ======================
83 
84 The typographical conventions used by this document are:
85 
86 * `Courier` denotes C and C++ source code.
87 
88 * <i>`Courier`</i> denotes XML content, JSON content, file and path names, and URIs.
89 
90 * <b>`Courier`</b> denotes HTTP content, text file content, and shell commands with command line options and arguments.
91 
92 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
93 "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to
94 be interpreted as described in RFC-2119.
95 
96 🔝 [Back to table of contents](#)
97 
98 Mapping WSDL and XML schemas to C/C++ {#tocpp}
99 =====================================
100 
101 To convert WSDL and XML schemas (XSD files) to code, we use the wsdl2h command
102 on the command line (or command prompt), after opening a terminal. The wsdl2h
103 command generates the data binding interface code that is saved to a special
104 Web services and data bindings interface header file with extension <i>`.h`</i>
105 that contains the WSDL service declarations and the data binding interface
106 declarations in a familiar C/C++ format:
107 
108  wsdl2h [options] -o file.h ... XSD and WSDL files ...
109 
110 This command converts WSDL and XSD files to C++ (or pure C with
111 <b>`wsdl2h -c`</b>) and saves the data binding interface to a interface header
112 file <i>`file.h`</i> that uses familiar C/C++ syntax extended with `//gsoap`
113 [directives](#directives) and annotations. Notational conventions are used in
114 the data binding interface to declare serializable C/C++ types and functions
115 for Web service operations.
116 
117 The WSDL 1.1/2.0, SOAP 1.1/1.2, and XSD 1.0/1.1 standards are supported by the
118 gSOAP tools. In addition, the most popular WS specifications are also
119 supported, including WS-Addressing, WS-ReliableMessaging, WS-Discovery,
120 WS-Security, WS-Policy, WS-SecurityPolicy, and WS-SecureConversation.
121 
122 This article focusses mainly on XML data bindings. XML data bindings for C/C++
123 bind XML schema types to C/C++ types. So integers in XML are bound to C
124 integers, strings in XML are bound to C or C++ strings, complex types in XML
125 are bound to C structs or C++ classes, and so on.
126 
127 A data binding is dual, meaning supporting a two way direction for development.
128 Either you start with WSDLs and/or XML schemas that are mapped to equivalent
129 C/C++ types, or you start with C/C++ types that are mapped to XSD types.
130 Either way, the end result is that you can serialize C/C++ types in XML such
131 that your XML is an instance of XML schema(s) and is validated against these
132 schema(s).
133 
134 This covers all of the following standard XSD components with their optional
135 attributes and properties:
136 
137 XSD component | attributes and properties
138 -------------- | -------------------------
139 schema | targetNamespace, version, elementFormDefault, attributeFormDefault, defaultAttributes
140 attribute | name, ref, type, use, default, fixed, form, targetNamespace, wsdl:arrayType
141 element | name, ref, type, default, fixed, form, nillable, abstract, substitutionGroup, minOccurs, maxOccurs, targetNamespace
142 simpleType | name
143 complexType | name, abstract, mixed, defaultAttributesApply
144 all | *n/a*
145 choice | minOccurs, maxOccurs
146 sequence | minOccurs, maxOccurs
147 group | name, ref, minOccurs, maxOccurs
148 attributeGroup | name, ref
149 any | minOccurs, maxOccurs
150 anyAttribute | *n/a*
151 
152 And also the following standard XSD directives are covered:
153 
154 directive | description
155 ---------- | -----------
156 import | Imports a schema into the importing schema for referencing
157 include | Include schema component definitions into a schema
158 override | Override by replacing schema component definitions
159 redefine | Extend or restrict schema component definitions
160 annotation | Annotates a component
161 
162 The XSD facets and their mappings to C/C++ are:
163 
164 XSD facet | maps to
165 -------------- | -------
166 enumeration | `enum`
167 simpleContent | class/struct wrapper with `__item` member
168 complexContent | class/struct
169 list | `enum*` bitmask (`enum*` enumerates a bitmask up to 64 bits)
170 extension | class/struct inheritance/extension
171 restriction | `typedef` and class/struct inheritance/redeclaration
172 length | `typedef` with restricted content length annotation
173 minLength | `typedef` with restricted content length annotation
174 maxLength | `typedef` with restricted content length annotation
175 minInclusive | `typedef` with numerical value range restriction annotation
176 maxInclusive | `typedef` with numerical value range restriction annotation
177 minExclusive | `typedef` with numerical value range restriction annotation
178 maxExclusive | `typedef` with numerical value range restriction annotation
179 precision | `typedef` with pattern annotation (pattern used for output, but input is not validated)
180 scale | `typedef` with pattern annotation (pattern used for output, but input is not validated)
181 totalDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
182 fractionDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
183 pattern | `typedef` with pattern annotation (define `soap::fsvalidate` callback to validate patterns)
184 union | string with union of value
185 
186 All primitive XSD types are supported, including but not limited to the
187 following XSD types:
188 
189 XSD type | maps to
190 ---------------- | -------
191 any/anyType | `_XML` string with literal XML content (or enable DOM with wsdl2h option `-d`)
192 anyURI | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
193 string | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
194 boolean | `bool` (C++) or `enum xsd__boolean` (C)
195 byte | `char` (i.e. `int8_t`)
196 short | `short` (i.e. `int16_t`)
197 int | `int` (i.e. `int32_t`)
198 long | `LONG64` (i.e. `long long` and `int64_t`)
199 unsignedByte | `unsigned char` (i.e. `uint8_t`)
200 unsignedShort | `unsigned short` (i.e. `uint16_t`)
201 unsignedInt | `unsigned int` (i.e. `uint32_t`)
202 unsignedLong | `ULONG64` (i.e. `unsigned long long` and `uint64_t`)
203 float | `float`
204 double | `double`
205 integer | string or `#import "custom/int128.h"` to use 128 bit `xsd__integer`
206 decimal | string or `#import "custom/long_double.h"` to use `long double`
207 precisionDecimal | string
208 duration | string or `#import "custom/duration.h"` to use 64 bit `xsd__duration`
209 dateTime | `time_t` or `#import "custom/struct_tm.h"` to use `struct tm` for `xsd__dateTime`
210 time | string or `#import "custom/long_time.h"` to use 64 bit `xsd__time`
211 date | string or `#import "custom/struct_tm_date.h"` to use `struct tm` for `xsd__date`
212 hexBinary | special class/struct `xsd__hexBinary`
213 base64Binary | special class/struct `xsd__base64Binary`
214 QName | `_QName` string (URI normalization rules are applied)
215 
216 All other primitive XSD types not listed above are mapped to strings, by
217 wsdl2h generating a `typedef` to string for these types. For example,
218 <i>`xsd:token`</i> is bound to a C++ or C string:
219 
220 ~~~{.cpp}
221  typedef std::string xsd__token; // C++
222  typedef char *xsd__token; // C (wsdl2h option -c)
223 ~~~
224 
225 This associates a compatible value space to the type with the appropriate XSD
226 type name used by the soapcpp2-generated serializers.
227 
228 It is possible to remap types by adding the appropriate mapping rules to
229 <i>`typemap.dat`</i> as we will explain in more detail in the next section.
230 
231 Imported custom serializers are intended to extend the C/C++ type bindings when
232 the default binding to string is not satisfactory to your taste and if the
233 target platform supports these C/C++ types. To add custom serializers to
234 <i>`typemap.dat`</i> for wsdl2h, see [adding custom serializers](#custom) below.
235 
236 🔝 [Back to table of contents](#)
237 
238 Using typemap.dat to customize data bindings {#typemap}
239 ============================================
240 
241 Use a <i>`typemap.dat`</i> file to redefine namespace prefixes and to customize type
242 bindings for the the generated header files produced by the wsdl2h tool. The
243 <i>`typemap.dat`</i> is the default file processed by wsdl2h. Use <b>`wsdl2h -tfile.dat`</b>
244 option <b>`-tfile.dat`</b> to specify a different mapping file <i>`file.dat`</i>.
245 
246 Declarations in <i>`typemap.dat`</i> can be broken up over multiple lines by
247 continuing on the next line by ending each line to be continued with a
248 backslash <b>`\`</b>. The limit is 4095 characters per line, whether the line is
249 broken up or not.
250 
251 🔝 [Back to table of contents](#)
252 
253 XML namespace bindings {#typemap1}
254 ----------------------
255 
256 The wsdl2h tool generates C/C++ type declarations that use `ns1`, `ns2`, etc.
257 as schema-binding URI prefixes. These default prefixes are generated somewhat
258 arbitrarily for each schema targetNamespace URI, meaning that their ordering
259 may change depending on the WSDL and XSD order of processing with wsdl2h.
260 
261 Therefore, it is **strongly recommended** to declare your own prefix for each
262 schema URI in <i>`typemap.dat`</i> to reduce maintaince effort of your code. This
263 is more robust when anticipating possible changes of the schema(s) and/or the
264 binding URI(s) and/or the tooling algorithms.
265 
266 The first and foremost important thing to do is to define prefix-URI bindings
267 for our C/C++ code by adding the following line(s) to our <i>`typemap.dat`</i> or make
268 a copy of this file and add the line(s) that bind our choice of prefix name to
269 each URI:
270 
271  prefix = "URI"
272 
273 For example, to use `g` as a prefix for the "urn:graph" XML namespace:
274 
275  g = "urn:graph"
276 
277 This produces `g__name` C/C++ type names that are bound to the "urn:graph"
278 schema by association of `g` to the generated C/C++ types.
279 
280 This means that <i>`<g:name xmlns:g="urn:graph">`</i> is parsed as an instance of a
281 `g__name` C/C++ type. Also <i>`<x:name xmlns:x="urn:graph">`</i> parses as an
282 instance of `g__name`, because the prefix <i>`x`</i> has the same URI value
283 <i>`urn:graph`</i>. Prefixes in XML have local scopes (like variables in a block).
284 
285 The first run of wsdl2h will reveal the XML namespace URIs, so you do not need
286 to search WSDLs and XSD files for all of the target namespaces. Just copy them
287 from the generated header file after the first run into <i>`typemap.dat`</i> for
288 editing.
289 
290 @note Only define a namespace prefix once in <i>`typemap.dat`</i>. That is, do not
291 use the same prefix for multiple XML namespace URIs. This is to avoid
292 namespace conflicts that may cause failed builds and failures in XML parsing
293 and XML schema validation.
294 
295 🔝 [Back to table of contents](#)
296 
297 XSD type bindings {#typemap2}
298 -----------------
299 
300 Custom C/C++ type bindings can be declared in <i>`typemap.dat`</i> to associate C/C++
301 types with specific schema types. These type bindings have four parts:
302 
303  prefix__type = declaration | use | ptr-use
304 
305 where
306 
307 - <b>`prefix__type`</b> is the schema type to be customized (the <b>`prefix__type`</b> name
308  uses the common double underscore naming convention);
309 
310 - <b>`declaration`</b> declares the C/C++ type in the wsdl2h-generated header file.
311  This part can be empty if no explicit declaration is needed;
312 
313 - <b>`use`</b> is an optional part that specifies how the C/C++ type is used in the
314  code. When omitted, it is the same as <b>`prefix__type`</b>;
315 
316 - <b>`ptr-use`</b> is an optional part that specifies how the type is used as a pointer
317  type. By default it is the <b>`use`</b> type name with a <b>`*`</b> or C++11
318  <b>`std::shared_ptr<type>`</b> when enabled (see further below). If <b>`use`</b> is already a
319  pointer type by the presence of a <b>`*`</b> in the <b>`use`</b> part, then the default
320  <b>`ptr-use`</b> type is the same as the <b>`use`</b> type (that is, no double
321  pointers <b>`**`</b> will be created in this case).
322 
323 For example, to map <i>`xsd:duration`</i> to a `long long` (`LONG64`) type that holds
324 millisecond duration values, we can use the custom serializer declared in
325 <i>`gsoap/custom/duration.h`</i> by adding the following line to <i>`typemap.dat`</i>:
326 
327  xsd__duration = #import "custom/duration.h"
328 
329 Here, we omitted the second and third parts, because `xsd__duration` is the
330 name that wsdl2h uses for this type in our generated code so we should leave
331 the <b>`use`</b> part unspecified. The third part is omitted to let wsdl2h use
332 `xsd__duration *` for pointers or `std::shared_ptr<xsd__duration>` if smart
333 pointers are enabled.
334 
335 To map <i>`xsd:string`</i> to `wchar_t*` wide strings for C source code output:
336 
337  xsd__string = | wchar_t* | wchar_t*
338 
339 For C++ we can use the `std::wstring` wide string:
340 
341  xsd__string = | std::wstring
342 
343 Note that the first part is empty, because these types do not require a
344 declaration. A <b>`ptr-use`</b> part is also defined for `wchar_t*`, but this
345 is actually needed because the wsdl2h tool recognizes that the <b>`use`</b>
346 part `wchar_t*` is already a pointer. By contrast, when using 8-bit strings,
347 it is recommended to use the `SOAP_C_UTFSTRING` flag to enable UTF-8 formatted
348 strings.
349 
350 When the <b>`ptr-use`</b> part is not specified, it will be auto-generated
351 as pointer `T*` for <b>`use`</b> type `T` or `std::shared_ptr<T>` when
352 the variable `$POINTER = std::shared`, see
353 [the special variables $CONTAINER, $POINTER, $SIZE and $OPTIONAL](#typemap5).
354 
355 The <b>`declaration`</b> part need not be empty, for example if a type must be
356 declared. For example:
357 
358  xsd__string = typedef std::string mystring; | mystring | std::optional<mystring>
359 
360 When a auto-generated <b>`declaration`</b> should be preserved but the
361 <b>`use`</b> or <b>`ptr-use`</b> parts must be redefined, then we use an
362 ellipsis for the <b>`declaration`</b> part:
363 
364  prefix__type = ... | use | ptr-use
365 
366 The <b>`ptr-use`</b> part is also useful to map schema polymorphic types to C
367 types for example, where we need to be able to both handle a base type and its
368 extensions as per schema extensibility. Say we have a base type called
369 <i>`ns:base`</i> that is extended, then we can remap this to a C type that
370 permits referening the extended types via a `void*` as follows:
371 
372  ns__base = ... | int __type_base; void*
373 
374 such that `__type_base` and `void*` will be used to (de)serialize any data
375 type, including base and its derived types. The `__type_base` integer is set
376 to a `SOAP_TYPE_T` value to indicate what type of data the `void*` pointer
377 points to.
378 
379 🔝 [Back to table of contents](#)
380 
381 Custom serializers for XSD types {#custom}
382 --------------------------------
383 
384 In the previous part we saw how a custom serializer is used to bind
385 <i>`xsd:duration`</i> to a `long long` (`LONG64` or `int64_t`) type to store millisecond
386 duration values:
387 
388  xsd__duration = #import "custom/duration.h"
389 
390 The `xsd__duration` type is an alias of `long long` (`LONG64` or `int64_t`).
391 
392 While wsdl2h will use this binding declared in <i>`typemap.dat`</i>
393 automatically, you will also need to compile <i>`gsoap/custom/duration.c`</i>.
394 Each custom serializer has an interface header file to be imported into another
395 interface header file that declares the custom type for soapcpp2 and a
396 serializer implementation file written in C, which should be compiled with the
397 application. You can compile these in C++ (rename files to <i>`.cpp`</i> if
398 needed).
399 
400 A custom serializer is declared in an interface header file for soapcpp2 using
401 `extern typedef`. The typedef name declared is serializable, whereas the
402 type on which it is based is not serializable. This declaration can be
403 combined with `volatile` when the type should not be redeclared, see
404 [volatile classes and structs](#toxsd9-2). For example, the custom serializer
405 for `struct tm` is the type `xsd__datetime` declared as follows in
406 `gsoap/custom/struct_tm.h`:
407 
408 ~~~{.cpp}
409  extern typedef volatile struct tm
410  {
411  int tm_sec; ///< seconds (0 - 60)
412  int tm_min; ///< minutes (0 - 59)
413  int tm_hour; ///< hours (0 - 23)
414  int tm_mday; ///< day of month (1 - 31)
415  int tm_mon; ///< month of year (0 - 11)
416  int tm_year; ///< year - 1900
417  int tm_wday; ///< day of week (Sunday = 0) (NOT USED)
418  int tm_yday; ///< day of year (0 - 365) (NOT USED)
419  int tm_isdst; ///< is summer time in effect?
420  char* tm_zone; ///< abbreviation of timezone (NOT USED)
421  } xsd__dateTime;
422 ~~~
423 
424 Another example is `xsd__duration` as a custom serializer for the C++11 type
425 `std::chrono::nanoseconds`:
426 
427 ~~~{.cpp}
428  extern typedef class std::chrono::nanoseconds xsd__duration;
429 ~~~
430 
431 Next, we present all pre-defined custom serializers that are available to you.
432 
433 🔝 [Back to table of contents](#)
434 
435 ### xsd:integer {#custom-1}
436 
437 The wsdl2h tool maps <i>`xsd:integer`</i> to a string by default. To map <i>`xsd:integer`</i> to
438 the 128 bit big int type `__int128_t`:
439 
440  xsd__integer = #import "custom/int128.h"
441 
442 The `xsd__integer` type is an alias of `__int128_t`.
443 
444 @warning Beware that the <i>`xsd:integer`</i> value space of integers is in principle
445 unbounded and values can be of arbitrary length. A value range fault
446 `SOAP_TYPE` (value exceeds native representation) or `SOAP_LENGTH` (value
447 exceeds range bounds) will be thrown by the deserializer if the value is out of
448 range.
449 
450 Other XSD integer types that are restrictions of <i>`xsd:integer`</i>, are
451 <i>`xsd:nonNegativeInteger`</i> and <i>`xsd:nonPositiveInteger`</i>, which are further restricted
452 by <i>`xsd:positiveInteger`</i> and <i>`xsd:negativeInteger`</i>. To bind these types to
453 `__int128_t` add the following definitions to <i>`typemap.dat`</i>:
454 
455  xsd__nonNegativeInteger = typedef xsd__integer xsd__nonNegativeInteger 0 : ;
456  xsd__nonPositiveInteger = typedef xsd__integer xsd__nonPositiveInteger : 0 ;
457  xsd__positiveInteger = typedef xsd__integer xsd__positiveInteger 1 : ;
458  xsd__negativeInteger = typedef xsd__integer xsd__negativeInteger : -1 ;
459 
460 Or simply uncomment these definitions in <i>`typemap.dat`</i> when you are using the
461 latest gSOAP releases.
462 
463 @note If `__int128_t` 128 bit integers are not supported on your platform and if it
464 is certain that <i>`xsd:integer`</i> values are within 64 bit value bounds for your
465 application's use, then you can map this type to `LONG64`:
466 
467  xsd__integer = typedef LONG64 xsd__integer;
468 
469 @note Again, a value range fault `SOAP_TYPE` or `SOAP_LENGTH` will be thrown by
470 the deserializer if the value is out of range.
471 
472 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/int128.c`</i> with your project.
473 
474 @see Section [numerical types](#toxsd5).
475 
476 🔝 [Back to table of contents](#)
477 
478 ### xsd:decimal {#custom-2}
479 
480 The wsdl2h tool maps <i>`xsd:decimal`</i> to a string by default. To map <i>`xsd:decimal`</i> to
481 extended precision floating point:
482 
483  xsd__decimal = #import "custom/long_double.h" | long double
484 
485 By contrast to all other custom serializers, this serializer enables `long
486 double` natively without requiring a new binding name (`xsd__decimal` is NOT
487 defined).
488 
489 If your system supports <i>`quadmath.h`</i> quadruple precision floating point
490 `__float128`, you can map <i>`xsd:decimal`</i> to `xsd__decimal` that is an alias of
491 `__float128`:
492 
493  xsd__decimal = #import "custom/float128.h"
494 
495 @warning Beware that <i>`xsd:decimal`</i> is in principle a decimal value with arbitraty
496 lengths. A value range fault `SOAP_TYPE` will be thrown by the deserializer if
497 the value is out of range.
498 
499 In the XML payload the special values <i>`INF`</i>, <i>`-INF`</i>, <i>`NaN`</i>
500 represent plus or minus infinity and not-a-number, respectively.
501 
502 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/long_double.c`</i> with your
503 project.
504 
505 @see Section [numerical types](#toxsd5).
506 
507 🔝 [Back to table of contents](#)
508 
509 ### xsd:dateTime {#custom-3}
510 
511 The wsdl2h tool maps <i>`xsd:dateTime`</i> to `time_t` by default.
512 
513 The trouble with `time_t` when represented as 32 bit `long` integers is that it
514 is limited to dates between 1970 and 2038. A 64 bit `time_t` is safe to use if
515 the target platform supports it, but lack of 64 bit `time_t` portability may
516 still cause date range issues.
517 
518 For this reason `struct tm` should be used to represent wider date ranges. This
519 custom serializer avoids using date and time information in `time_t`. You get
520 the raw date and time information. You only lose the day of the week
521 information. It is always Sunday (`tm_wday=0`).
522 
523 To map <i>`xsd:dateTime`</i> to `xsd__dateTime` which is an alias of `struct tm`:
524 
525  xsd__dateTime = #import "custom/struct_tm.h"
526 
527 If the limited date range of `time_t` is not a problem but you want to increase
528 the time precision with fractional seconds, then we suggest to map <i>`xsd:dateTime`</i>
529 to `struct timeval`:
530 
531  xsd__dateTime = #import "custom/struct_timeval.h"
532 
533 If the limited date range of `time_t` is not a problem but you want to use the
534 C++11 time point type `std::chrono::system_clock::time_point` (which internally
535 uses `time_t`):
536 
537  xsd__dateTime = #import "custom/chrono_time_point.h"
538 
539 Again, we should make sure that the dates will not exceed the date range when
540 using the default `time_t` binding for <i>`xsd:dateTime`</i> or when binding
541 <i>`xsd:dateTime`</i> to `struct timeval` or to `std::chrono::system_clock::time_point`.
542 These are safe to use in applications that use <i>`xsd:dateTime`</i> to record date
543 stamps within a given window. Otherwise, we recommend the `struct tm` custom
544 serializer.
545 
546 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/struct_tm.c`</i> with your
547 project.
548 
549 You could even map <i>`xsd:dateTime`</i> to a plain string (use `char*` with C and
550 `std::string` with C++). For example:
551 
552  xsd__dateTime = | char*
553 
554 @see Section [date and time types](#toxsd7).
555 
556 🔝 [Back to table of contents](#)
557 
558 ### xsd:date {#custom-4}
559 
560 The wsdl2h tool maps <i>`xsd:date`</i> to a string by default. We can map <i>`xsd:date`</i> to
561 `struct tm`:
562 
563  xsd__date = #import "custom/struct_tm_date.h"
564 
565 The `xsd__date` type is an alias of `struct tm`. The serializer ignores the
566 time part and the deserializer only populates the date part of the struct,
567 setting the time to 00:00:00. There is no unreasonable limit on the date range
568 because the year field is stored as an integer (`int`).
569 
570 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/struct_tm_date.c`</i> with your
571 project.
572 
573 @see Section [date and time types](#toxsd7).
574 
575 🔝 [Back to table of contents](#)
576 
577 ### xsd:time {#custom-5}
578 
579 The wsdl2h tool maps <i>`xsd:time`</i> to a string by default. We can map <i>`xsd:time`</i> to
580 an `unsigned long long` (`ULONG64` or `uint64_t`) integer with microsecond time
581 precision:
582 
583  xsd__time = #import "custom/long_time.h"
584 
585 This type represents 00:00:00.000000 to 23:59:59.999999, from `0` to an upper
586 bound of `86399999999`. A microsecond resolution means that a 1 second
587 increment requires an increment of 1000000 in the integer value. The serializer
588 adds a UTC time zone.
589 
590 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/long_time.c`</i> with your
591 project.
592 
593 @see Section [date and time types](#toxsd7).
594 
595 🔝 [Back to table of contents](#)
596 
597 ### xsd:duration {#custom-6}
598 
599 The wsdl2h tool maps <i>`xsd:duration`</i> to a string by default, unless <i>`xsd:duration`</i>
600 is mapped to a `long long` (`LONG64` or `int64_t`) type with with millisecond
601 (ms) time duration precision:
602 
603  xsd__duration = #import "custom/duration.h"
604 
605 The `xsd__duration` type is a 64 bit signed integer that can represent
606 106,751,991,167 days forwards (positive) and backwards (negative) in time in
607 increments of 1 ms (1/1000 of a second).
608 
609 Rescaling of the duration value by may be needed when adding the duration value
610 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
611 depending on the platform and possible changes to `time_t`.
612 
613 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
614 value to a `std::chrono::system_clock::time_point` value. To use
615 `std::chrono::nanoseconds` as <i>`xsd:duration`</i>:
616 
617  xsd__duration = #import "custom/chrono_duration.h"
618 
619 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
620 backwards in time in increments of 1 ns (1/1,000,000,000 of a second).
621 
622 Certain observations with respect to receiving durations in years and months
623 apply to both of these serializer decoders for <i>`xsd:duration`</i>.
624 
625 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/duration.c`</i> with your
626 project.
627 
628 @see Section [time duration types](#toxsd8).
629 
630 🔝 [Back to table of contents](#)
631 
632 Custom Qt serializers for XSD types {#qt}
633 -----------------------------------
634 
635 The gSOAP distribution includes several custom serializers for Qt types. Also
636 Qt container classes are supported, see
637 [the special variables $CONTAINER, $POINTER, $SIZE and $OPTIONAL](#typemap5).
638 
639 This feature requires gSOAP 2.8.34 or higher and Qt 4.8 or higher.
640 
641 Each Qt custom serializer has an interface header file for soapcpp2 and a C++
642 implementation file to be compiled with your project.
643 
644 Other Qt primitive types that are Qt `typedef`s of C/C++ types do not require a
645 custom serializer.
646 
647 🔝 [Back to table of contents](#)
648 
649 ### xsd:string {#qt-1}
650 
651 To use Qt strings instead of C++ strings, add the following definition to
652 <i>`typemap.dat`</i>:
653 
654  xsd__string = #import "custom/qstring.h"
655 
656 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qstring.cpp`</i> with your
657 project.
658 
659 🔝 [Back to table of contents](#)
660 
661 ### xsd:base64Binary {#qt-2}
662 
663 To use Qt byte arrays for <i>`xsd:base64Binary`</i> instead of the
664 `xsd__base64Binary` class, add the following definition to <i>`typemap.dat`</i>:
665 
666  xsd__base64Binary = #import "custom/qbytearray_base64.h"
667 
668 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qbytearray_base64.cpp`</i> with
669 your project.
670 
671 🔝 [Back to table of contents](#)
672 
673 ### xsd:hexBinary {#qt-3}
674 
675 To use Qt byte arrays for <i>`xsd:hexBinary`</i> instead of the `xsd__base64Binary`
676 class, add the following definition to <i>`typemap.dat`</i>:
677 
678  xsd__hexBinary = #import "custom/qbytearray_hex.h"
679 
680 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qbytearray_hex.cpp`</i> with
681 your project.
682 
683 🔝 [Back to table of contents](#)
684 
685 ### xsd:dateTime {#qt-4}
686 
687 To use Qt QDateTime for <i>`xsd:dateTime`</i>, add the following definition to
688 <i>`typemap.dat`</i>:
689 
690  xsd__dateTime = #import "custom/datetime.h"
691 
692 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qdatetime.cpp`</i> with
693 your project.
694 
695 🔝 [Back to table of contents](#)
696 
697 ### xsd:date {#qt-5}
698 
699 To use Qt QDate for <i>`xsd:date`</i>, add the following definition to
700 <i>`typemap.dat`</i>:
701 
702  xsd__date = #import "custom/qdate.h"
703 
704 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qdate.cpp`</i> with your
705 project.
706 
707 🔝 [Back to table of contents](#)
708 
709 ### xsd:time {#qt-6}
710 
711 To use Qt QDate for <i>`xsd:time`</i>, add the following definition to
712 <i>`typemap.dat`</i>:
713 
714  xsd__time = #import "custom/qtime.h"
715 
716 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qtime.cpp`</i> with your
717 project.
718 
719 🔝 [Back to table of contents](#)
720 
721 Class/struct member additions {#typemap3}
722 -----------------------------
723 
724 All generated classes and structs can be augmented with additional
725 members such as methods, constructors and destructors, and private members:
726 
727  prefix__type = $ member-declaration
728 
729 For example, we can add method declarations and private members to a class, say
730 `ns__record` as follows:
731 
732  ns__record = $ ns__record(const ns__record &); // copy constructor
733  ns__record = $ void print(); // a print method
734  ns__record = $ private: int status; // a private member
735 
736 Method declarations cannot include any code, because soapcpp2's input permits
737 only type declarations, not code.
738 
739 🔝 [Back to table of contents](#)
740 
741 Replacing XSD types by equivalent alternatives {#typemap4}
742 ----------------------------------------------
743 
744 Type replacements can be given to replace one type entirely with another given
745 type:
746 
747  prefix__type1 == prefix__type2
748 
749 This replaces all `prefix__type1` by `prefix__type2` in the wsdl2h output.
750 
751 @warning Do not agressively replace types, because this can cause XML schema
752 validation to fail when a value-type mismatch is encountered in the XML input.
753 Therefore, only replace similar types with other similar types that are wider
754 (e.g. `short` by `int` and `float` by `double`).
755 
756 🔝 [Back to table of contents](#)
757 
758 The special variables $CONTAINER, $POINTER, $SIZE and $OPTIONAL {#typemap5}
759 ---------------------------------------------------------------
760 
761 The <i>`typemap.dat`</i> <b>`$CONTAINER`</b> variable defines the container type to use in
762 the wsdl2h-generated declarations for C++, which is `std::vector` by default.
763 For example, to use `std::list` as the container in the wsdl2h-generated
764 declarations we add the following line to <i>`typemap.dat`</i>:
765 
766  $CONTAINER = std::list
767 
768 Also a Qt container can be used instead of the default `std::vector`, for
769 example `QVector`:
770 
771  [
772  #include <QVector>
773  ]
774  $CONTAINER = QVector
775 
776 To remove containers, use <b>`wsdl2h -s`</b>. This also removes `std::string`,
777 but you can re-introduce `std::string` with
778 <b>`xsd__string = | std::string`</b> in <i>`typemap.dat`</i>.
779 
780 The <i>`typemap.dat`</i> <b>`$POINTER`</b> variable defines the smart pointer to use in the
781 wsdl2h-generated declarations for C++, which replaces the use of `*` pointers.
782 For example:
783 
784  $POINTER = std::shared_ptr
785 
786 Not all pointers in the generated output are replaced by smart pointers by
787 wsdl2h, such as pointers as union members and pointers as struct/class members
788 that point to arrays of values.
789 
790 @note The standard smart pointer `std::shared_ptr` is generally safe to use.
791 Other smart pointers such as `std::unique_ptr` and `std::auto_ptr` may cause
792 compile-time errors when classes have smart pointer members but no copy
793 constructor (a default copy constructor). A copy constructor is required for
794 non-shared smart pointer copying or swapping.
795 
796 Alternatives to `std::shared_ptr` of the form `NAMESPACE::shared_ptr` can be
797 assigned to <b>`$POINTER`</b> when the namespace `NAMESPACE` also implements
798 `NAMESPACE::make_shared` and when the shared pointer class provides `reset()`
799 and`get()` methods and the dereference operator. For example Boost
800 `boost::shared_ptr`:
801 
802  [
803  #include <boost/shared_ptr.hpp>
804  ]
805  $POINTER = boost::shared_ptr
806 
807 The user-defined content between <b>`[`</b> and <b>`]`</b> ensures that we include the Boost
808 header files that are needed to support `boost::shared_ptr` and
809 `boost::make_shared`.
810 
811 The variable <b>`$SIZE`</b> defines the type of array sizes, which is `int` by
812 default. For example, to change array size types to `size_t`:
813 
814  $SIZE = size_t
815 
816 Permissible types are `int` and `size_t`. This variable does not affect the
817 size of dynamic arrays, `xsd__hexBinary` and `xsd__base64Binary` types, which
818 is always `int`.
819 
820 When C++17 is enabled with wsdl2h and soapcpp2 option <b>`-c++17`</b>, you can
821 also semi-automatically enable `std::optional` declarations with optional class
822 and structure member variables. This means that `std::optional` is used
823 instead of a (smart) pointer to make a member optional.
824 
825 To enable `std::optional` with member variables that are primitive types,
826 `typedef`, and `enum` automatically:
827 
828  $OPTIONAL = std::optional
829 
830 Local unnamed simpleType restrictions may not adopt the specified optional type
831 and still use pointers instead. This limitation may be lifted in a future
832 release.
833 
834 🔝 [Back to table of contents](#)
835 
836 User-defined content {#typemap6}
837 --------------------
838 
839 Any other content to be generated by wsdl2h can be included in <i>`typemap.dat`</i> by
840 enclosing it within brackets <b>`[`</b> and <b>`]`</b> anywhere in the <i>`typemap.dat`</i> file.
841 Each of the two brackets must appear at the start of a new line.
842 
843 For example, we can add an `#import "wsa5.h"` to the wsdl2h-generated output as
844 follows:
845 
846  [
847  #import "import/wsa5.h"
848  ]
849 
850 which emits the `#import "import/wsa5.h"` literally at the start of the
851 wsdl2h-generated header file.
852 
853 🔝 [Back to table of contents](#)
854 
855 Mapping C/C++ to XML schema {#toxsd}
856 ===========================
857 
858 The soapcpp2 command generates the data binding implementation code from a data
859 binding interface <i>`file.h`</i>:
860 
861  soapcpp2 [options] file.h
862 
863 where <i>`file.h`</i> is a interface header file that declares the XML data
864 binding interface. The <i>`file.h`</i> is typically generated by wsdl2h, but
865 you can also declare one yourself. If so, add `//gsoap`
866 [directives](#directives) and declare in this file all our C/C++ types you want
867 to serialize in XML.
868 
869 You can also declare functions that will be converted to Web service operations
870 by soapcpp2. Global function declarations define service operations, which are
871 of the form:
872 
873 ~~~{.cpp}
874  int prefix__func(arg1, arg2, ..., argn, result);
875 ~~~
876 
877 where `arg1`, `arg2`, ..., `argn` are formal argument declarations of the input
878 and `result` is a formal argument for the output, which must be a pointer or
879 reference to the result object to be populated. More information on declaring
880 and implementing service operation functions can be found in the
881 [gSOAP user guide.](../../guide/html/index.html)
882 
883 🔝 [Back to table of contents](#)
884 
885 Overview of serializable C/C++ types {#toxsd1}
886 ------------------------------------
887 
888 The following C/C++ types are supported by soapcpp2 and mapped to XSD types
889 and constructs. See the subsections below for more details or follow the links.
890 
891 🔝 [Back to table of contents](#)
892 
893 ### List of Boolean types
894 
895 Boolean Type | Notes
896 ----------------------------- | -----
897 `bool` | C++ bool
898 `enum xsd__boolean` | C alternative to C++ `bool` with `false_` and `true_`
899 
900 @see Section [C++ bool and C alternative](#toxsd3).
901 
902 🔝 [Back to table of contents](#)
903 
904 ### List of enumeration and bitmask types
905 
906 Enumeration Type | Notes
907 ----------------------------- | -----
908 `enum` | enumeration
909 `enum class` | C++11 scoped enumeration, requires `soapcpp2 -c++11`
910 `enum*` | a bitmask that enumerates values 1, 2, 4, 8, ...
911 `enum* class` | C++11 scoped enumeration bitmask, requires `soapcpp2 -c++11`
912 
913 @see Section [enumerations and bitmasks](#toxsd4).
914 
915 🔝 [Back to table of contents](#)
916 
917 ### List of numerical types
918 
919 Numerical Type | Notes
920 ----------------------------- | -----
921 `char` | byte
922 `short` | 16 bit integer
923 `int` | 32 bit integer
924 `long` | 32 bit integer
925 `LONG64` | 64 bit integer
926 `xsd__integer` | 128 bit integer, use `#import "custom/int128.h"`
927 `long long` | same as `LONG64`
928 `unsigned char` | unsigned byte
929 `unsigned short` | unsigned 16 bit integer
930 `unsigned int` | unsigned 32 bit integer
931 `unsigned long` | unsigned 32 bit integer
932 `ULONG64` | unsigned 64 bit integer
933 `unsigned long long` | same as `ULONG64`
934 `int8_t` | same as `char`
935 `int16_t` | same as `short`
936 `int32_t` | same as `int`
937 `int64_t` | same as `LONG64`
938 `uint8_t` | same as `unsigned char`
939 `uint16_t` | same as `unsigned short`
940 `uint32_t` | same as `unsigned int`
941 `uint64_t` | same as `ULONG64`
942 `size_t` | transient type (not serializable)
943 `float` | 32 bit float
944 `double` | 64 bit float
945 `long double` | extended precision float, use `#import "custom/long_double.h"`
946 `xsd__decimal` | `quadmath.h` library 128 bit quadruple precision float, use `#import "custom/float128.h"`
947 `typedef` | declares a type name, with optional value range and string length bounds
948 
949 @see Section [numerical types](#toxsd5).
950 
951 🔝 [Back to table of contents](#)
952 
953 ### List of string types
954 
955 String Type | Notes
956 ----------------------------- | -----
957 `char*` | string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
958 `wchar_t*` | wide string
959 `std::string` | C++ string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
960 `std::wstring` | C++ wide string
961 `char[N]` | fixed-size string, requires `soapcpp2 -b`
962 `_QName` | normalized QName content
963 `_XML` | literal XML string content with wide characters in UTF-8
964 `typedef` | declares a new string type name, may restrict string length
965 
966 @see Section [string types](#toxsd6).
967 
968 🔝 [Back to table of contents](#)
969 
970 ### List of date and time types
971 
972 Date and Time Type | Notes
973 --------------------------------------- | -----
974 `time_t` | date and time point since epoch
975 `struct tm` | date and time point, use `#import "custom/struct_tm.h"`
976 `struct tm` | date point, use `#import "custom/struct_tm_date.h"`
977 `struct timeval` | date and time point, use `#import "custom/struct_timeval.h"`
978 `unsigned long long` | time point in microseconds, use `#import "custom/long_time.h"`
979 `std::chrono::system_clock::time_point` | date and time point, use `#import "custom/chrono_time_point.h"`
980 
981 @see Section [date and time types](#toxsd7).
982 
983 🔝 [Back to table of contents](#)
984 
985 ### List of time duration types
986 
987 Time Duration Type | Notes
988 ----------------------------- | -----
989 `long long` | duration in milliseconds, use `#import "custom/duration.h"`
990 `std::chrono::nanoseconds` | duration in nanoseconds, use `#import "custom/chrono_duration.h"`
991 
992 @see Section [time duration types](#toxsd8).
993 
994 🔝 [Back to table of contents](#)
995 
996 ### List of classes, structs, unions, pointers, containers, and arrays
997 
998 Classes, Structs, and Members | Notes
999 ----------------------------- | -----
1000 `class` | C++ class with single inheritance only
1001 `struct` | C struct or C++ struct without inheritance
1002 `std::shared_ptr<T>` | C++11 smart shared pointer
1003 `std::unique_ptr<T>` | C++11 smart pointer
1004 `std::auto_ptr<T>` | C++ smart pointer
1005 `std::deque<T>` | use `#import "import/stldeque.h"`
1006 `std::list<T>` | use `#import "import/stllist.h"`
1007 `std::vector<T>` | use `#import "import/stlvector.h"`
1008 `std::set<T>` | use `#import "import/stlset.h"`
1009 `template<T> class` | a container with `begin()`, `end()`, `size()`, `clear()`, and `insert()` methods
1010 `T*` | pointer to data of type `T`
1011 `T*` | as a class or struct member: points to data of type `T` or array of `T` with member `__size`
1012 `T[N]` | as a class or struct member: fixed-size array of type `T`
1013 `union` | as a class or struct member: requires a variant selector member `__union`
1014 `void*` | as a class or struct member: requires a `__type` member to indicate the type of object pointed to
1015 
1016 @see Section [classes and structs](#toxsd9).
1017 
1018 🔝 [Back to table of contents](#)
1019 
1020 ### List of special classes and structs
1021 
1022 Special Classes and Structs | Notes
1023 ----------------------------- | -----
1024 Special Array class/struct | single and multidimensional SOAP Arrays
1025 Special Wrapper class/struct | complexTypes with simpleContent, wraps `__item` member
1026 `xsd__hexBinary` | binary content
1027 `xsd__base64Binary` | binary content and optional DIME/MIME/MTOM attachments
1028 `xsd__anyType` | DOM elements, use `#import "dom.h"`
1029 `@xsd__anyAttribute` | DOM attributes, use `#import "dom.h"`
1030 
1031 @see Section [special classes and structs](#toxsd10).
1032 
1033 🔝 [Back to table of contents](#)
1034 
1035 Colon notation versus name prefixing with XML tag name translation {#toxsd2}
1036 ------------------------------------------------------------------
1037 
1038 To bind C/C++ type names to XSD types, a simple form of name prefixing is used
1039 by the gSOAP tools by prepending the XML namespace prefix to the C/C++ type
1040 name with a pair of undescrores. This also ensures that name clashes cannot
1041 occur when multiple WSDL and XSD files are converted to C/C++. Also, C++
1042 namespaces are not sufficiently rich to capture XML schema namespaces
1043 accurately, for example when class members are associated with schema elements
1044 defined in another XML namespace and thus the XML namespace scope of the
1045 member's name is relevant, not just its type.
1046 
1047 However, from a C/C++ centric point of view this can be cumbersome. Therefore,
1048 colon notation is an alternative to physically augmenting C/C++ names with
1049 prefixes.
1050 
1051 For example, the following class uses colon notation to bind the `record` class
1052 to the <i>`urn:types`</i> schema:
1053 
1054 ~~~{.cpp}
1055  //gsoap ns schema namespace: urn:types
1056  class ns:record // binding 'ns:' to a type name
1057  {
1058  public:
1059  std::string name;
1060  uint64_t SSN;
1061  ns:record *spouse; // using 'ns:' with the type name
1062  ns:record(); // using 'ns:' here too
1063  ~ns:record(); // and here
1064  };
1065 ~~~
1066 
1067 The colon notation is stripped away by soapcpp2 when generating the data
1068 binding implementation code for our project. So the final code just uses
1069 `record` to identify this class and its constructor/destructor.
1070 
1071 When using colon notation make sure to be consistent and not use colon notation
1072 mixed with prefixed forms. The qualified name `ns:record` differs from
1073 `ns__record`, because `ns:record` is compiled to an unqualified `record` name
1074 in the source code output by the soapcpp2 tool.
1075 
1076 Colon notation also facilitates overruling the elementFormDefault and
1077 attributeFormDefault declaration that is applied to local elements and
1078 attributes, when declared as members of classes, structs, and unions. With
1079 colon notation for class, struct and union members, the corresponding XML
1080 elements and attributes are selectively qualified with the specified prefix or
1081 unqualified when the prefix is omitted in front of the colon. For more
1082 details, see [qualified and unqualified members](#toxsd9-6).
1083 
1084 A C/C++ identifier name (a type name, member name, function name, or parameter
1085 name) is translated to an XML tag name by the following rules:
1086 
1087 - Two leading underscores indicates that the identifier name has no XML tag
1088  name, i.e. this name is not visible in XML and is not translated.
1089 
1090 - A leading underscore is removed, but the underscore indicates that: **a**) a
1091  struct/class member name or parameter name has a wildcard XML tag name (i.e.
1092  matches any XML tag), or **b**) a type name that has a
1093  [document root element definition](#toxsd9-7).
1094 
1095 - Trailing underscores are removed (i.e. trailing underscores can be used to
1096  avoid name clashes with keywords).
1097 
1098 - Two underscores `__` in a name represent the namespace prefix of a name.
1099 
1100 - A colon (`:`) within a name represent the namespace prefix of a name that is
1101  present in XML, but this prefix is not present in the generated C/C++ code.
1102 
1103 - A leading colon (`:`) before a name makes the name unqualified in XML.
1104 
1105 - Underscores within names are translated to hyphens (hyphens are more common
1106  in XML tag names).
1107 
1108 - `_USCORE` is translated to an underscore in the translated XML tag name.
1109 
1110 - `_DOT` is translated to a dot (<i>`.`</i>) in the translated XML tag name.
1111 
1112 - `_xHHHH` is translated to the Unicode character with code point HHHH (hex).
1113 
1114 - C++11 Unicode identifier name characters in UTF-8 are translated as-is.
1115 
1116 For example, the C/C++ identifier name `s_a__my_way` is represented in XML
1117 by the tag name <i>`s-a:my-way`</i> by translating the prefix `s_a` and the
1118 local name `my_way`. With colon notation, the colon-qualified C/C++ identifier
1119 name `s_a:my_way` is also represented in XML by the same tag name
1120 <i>`s-a:my-way`</i>, but the generated C/C++ source code defines and uses the
1121 local name `my_way` only.
1122 
1123 Struct/class member and parameter name translation can be overruled by using
1124 [backtick XML tags](#toxsd9-5-1) (with gSOAP 2.8.30 and greater).
1125 
1126 🔝 [Back to table of contents](#)
1127 
1128 C++ bool and C alternative {#toxsd3}
1129 --------------------------
1130 
1131 The C++ `bool` type is bound to built-in XSD type <i>`xsd:boolean`</i>.
1132 
1133 The C alternative is to define an enumeration:
1134 
1135 ~~~{.cpp}
1136  enum xsd__boolean { false_, true_ };
1137 ~~~
1138 
1139 or by defining an enumeration in C with pseudo-scoped enumeration constants:
1140 
1141 ~~~{.cpp}
1142  enum xsd__boolean { xsd__boolean__false, xsd__boolean__true };
1143 ~~~
1144 
1145 The XML value space of these types is <i>`false`</i> and <i>`true`</i>, but also accepted
1146 are <i>`0`</i> and <i>`1`</i> values for <i>`false`</i> and <i>`true`</i>, respectively.
1147 
1148 To prevent name clashes, `false_` and `true_` have a trailing underscore in
1149 their `enum` symbols. Trailing underscores are removed from the XML value space.
1150 
1151 🔝 [Back to table of contents](#)
1152 
1153 Enumerations and bitmasks {#toxsd4}
1154 -------------------------
1155 
1156 Enumerations are mapped to XSD simpleType enumeration restrictions of
1157 <i>`xsd:string`</i>, <i>`xsd:QName`</i>, and <i>`xsd:long`</i>.
1158 
1159 Consider for example:
1160 
1161 ~~~{.cpp}
1162  enum ns__Color { RED, WHITE, BLUE };
1163 ~~~
1164 
1165 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1166 schema:
1167 
1168 <div class="alt">
1169 ~~~{.xml}
1170  <simpleType name="Color">
1171  <restriction base="xsd:string">
1172  <enumeration value="RED"/>
1173  <enumeration value="WHITE"/>
1174  <enumeration value="BLUE"/>
1175  </restriction>
1176  </simpleType>
1177 ~~~
1178 </div>
1179 
1180 Enumeration name constants can be pseudo-scoped to prevent name clashes,
1181 because enumeration name constants have a global scope in C and C++:
1182 
1183 ~~~{.cpp}
1184  enum ns__Color { ns__Color__RED, ns__Color__WHITE, ns__Color__BLUE };
1185 ~~~
1186 
1187 You can also use C++11 scoped enumerations to prevent name clashes:
1188 
1189 ~~~{.cpp}
1190  enum class ns__Color : int { RED, WHITE, BLUE };
1191 ~~~
1192 
1193 Here, the enumeration class base type `: int` is optional. In place of `int`
1194 in the example above, we can also use `int8_t`, `int16_t`, `int32_t`, or
1195 `int64_t`.
1196 
1197 The XML value space of the enumertions defined above is <i>`RED`</i>, <i>`WHITE`</i>, and
1198 <i>`BLUE`</i>.
1199 
1200 Prefix-qualified enumeration name constants are mapped to simpleType
1201 restrictions of <i>`xsd:QName`</i>, for example:
1202 
1203 ~~~{.cpp}
1204  enum ns__types { xsd__int, xsd__float };
1205 ~~~
1206 
1207 which maps to a simpleType restriction of <i>`xsd:QName`</i> in the soapcpp2-generated
1208 schema:
1209 
1210 <div class="alt">
1211 ~~~{.xml}
1212  <simpleType name="types">
1213  <restriction base="xsd:QName">
1214  <enumeration value="xsd:int"/>
1215  <enumeration value="xsd:float"/>
1216  </restriction>
1217  </simpleType>
1218 ~~~
1219 </div>
1220 
1221 Enumeration name constants can be pseudo-numeric as follows:
1222 
1223 ~~~{.cpp}
1224  enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1225 ~~~
1226 
1227 which maps to a simpleType restriction of <i>`xsd:long`</i>:
1228 
1229 <div class="alt">
1230 ~~~{.xml}
1231  <simpleType name="Color">
1232  <restriction base="xsd:long">
1233  <enumeration value="3"/>
1234  <enumeration value="5"/>
1235  <enumeration value="7"/>
1236  <enumeration value="11"/>
1237  </restriction>
1238  </simpleType>
1239 ~~~
1240 </div>
1241 
1242 The XML value space of this type is <i>`3`</i>, <i>`5`</i>, <i>`7`</i>, and <i>`11`</i>.
1243 
1244 Besides (pseudo-) scoped enumerations, another way to prevent name clashes
1245 accross enumerations is to start an enumeration name constant with one
1246 underscore or followed it by any number of underscores, which makes it
1247 unique. The leading and trailing underscores are removed from the XML value
1248 space.
1249 
1250 ~~~{.cpp}
1251  enum ns__ABC { A, B, C };
1252  enum ns__BA { B, A }; // BAD: B = 1 but B is already defined as 2
1253  enum ns__BA_ { B_, A_ }; // OK
1254 ~~~
1255 
1256 The gSOAP soapcpp2 tool permits reusing enumeration name constants across
1257 (non-scoped) enumerations as long as these values are assigned the same
1258 constant. Therefore, the following is permitted:
1259 
1260 ~~~{.cpp}
1261  enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1262  enum ns__Throws { _1 = 1, _2 = 2, _3 = 3, _4 = 4, _5 = 5, _6 = 6 };
1263 ~~~
1264 
1265 A bitmask type is an `enum*` "product enumeration" with a geometric,
1266 power-of-two sequence of values assigned to the enumeration constants:
1267 
1268 ~~~{.cpp}
1269  enum* ns__Options { SSL3, TLS10, TLS11, TLS12, TLS13 };
1270 ~~~
1271 
1272 where the product enum assigns 1 to `SSL3`, 2 to `TLS10`, 4 to `TLS11`, 8
1273 to `TLS12`, and 16 to `TLS13`, which allows these enumeration constants to be
1274 used in composing bitmasks with `|` (bitwise or) `&` (bitwise and), and `~`
1275 (bitwise not):
1276 
1277 ~~~{.cpp}
1278  enum ns__Options options = (enum ns__Options)(SSL3 | TLS10 | TLS11 | TLS12 | TLS13);
1279  if (options & SSL3) // if SSL3 is an option, warn and remove from options
1280  {
1281  warning();
1282  options &= ~SSL3;
1283  }
1284 ~~~
1285 
1286 The bitmask type maps to a simpleType list restriction of <i>`xsd:string`</i> in the
1287 soapcpp2-generated XML schema:
1288 
1289 <div class="alt">
1290 ~~~{.xml}
1291  <simpleType name="Options">
1292  <list>
1293  <restriction base="xsd:string">
1294  <enumeration value="SSL3"/>
1295  <enumeration value="TLS10"/>
1296  <enumeration value="TLS11"/>
1297  <enumeration value="TLS12"/>
1298  <enumeration value="TLS13"/>
1299  </restriction>
1300  </list>
1301  </simpleType>
1302 ~~~
1303 </div>
1304 
1305 The XML value space of this type consists of all 16 possible subsets of the
1306 four values, represented by an XML string with space-separated values. For
1307 example, the bitmask `TLS10 | TLS11 | TLS12` equals 14 and is represented by
1308 the XML text <i>`TLS10 TLS11 TLS12`</i>.
1309 
1310 You can also use C++11 scoped enumerations with bitmasks using `enum*` product
1311 enumerations:
1312 
1313 ~~~{.cpp}
1314  enum* class ns__Options { SSL3, TLS10, TLS11, TLS12, TLS13 };
1315 ~~~
1316 
1317 The base type of a scoped enumeration bitmask, when explicitly given, is
1318 ignored. The base type is either `int` or `int64_t`, depending on the number
1319 of constants enumerated in the bitmask.
1320 
1321 To convert `enum` name constants and bitmasks to a string, we use the
1322 auto-generated function for enum `T`:
1323 
1324 ~~~{.cpp}
1325  const char *soap_T2s(struct soap*, enum T val)
1326 ~~~
1327 
1328 The string returned is stored in an internal buffer of the current `soap`
1329 context, so you should copy it to keep it from being overwritten. For example,
1330 use `char *soap_strdup(struct soap*, const char*)`.
1331 
1332 To convert a string to an `enum` constant or bitmask, we use the auto-generated
1333 function
1334 
1335 ~~~{.cpp}
1336  int soap_s2T(struct soap*, const char *str, enum T *val)
1337 ~~~
1338 
1339 This function takes the name (or names, space-separated for bitmasks) of
1340 the enumeration constant in a string `str`. Names should be given without the
1341 pseudo-scope prefix and without trailing underscores. The function sets `val`
1342 to the corresponding integer enum constant or to a bitmask. The function
1343 returns `SOAP_OK` (zero) on success or an error if the string is not a valid
1344 enumeration name.
1345 
1346 🔝 [Back to table of contents](#)
1347 
1348 Numerical types {#toxsd5}
1349 ---------------
1350 
1351 Integer and floating point types are mapped to the equivalent built-in XSD
1352 types with the same sign and bit width.
1353 
1354 The `size_t` type is transient (not serializable) because its width is platform
1355 dependent. We recommend to use `uint64_t` instead.
1356 
1357 The XML value space of integer types are their decimal representations without
1358 loss of precision.
1359 
1360 The XML value space of floating point types are their decimal representations.
1361 The decimal representations are formatted with the printf format string `"%.9G"`
1362 for floats and the printf format string `"%.17lG"` for double. To change the
1363 format strings, we can assign new strings to the following `soap` context
1364 members:
1365 
1366 ~~~{.cpp}
1367  soap.float_format = "%g";
1368  soap.double_format = "%lg";
1369  soap.long_double_format = "%Lg";
1370 ~~~
1371 
1372 Decimal representations may result in a loss of precision of the least
1373 significant decimal. Therefore, the format strings that are used by default
1374 are sufficiently precise to avoid loss, but this may result in long decimal
1375 fractions in the XML value space.
1376 
1377 The `long double` extended floating point type requires a custom serializer:
1378 
1379 ~~~{.cpp}
1380  #import "custom/long_double.h"
1381  ... // use long double
1382 ~~~
1383 
1384 You can now use `long double`, which has a serializer that serializes this type
1385 as <i>`xsd:decimal`</i>. Compile and link your code with the file
1386 <i>`gsoap/custom/long_double.c`</i>.
1387 
1388 The value space of floating point values includes the special values
1389 <i>`INF`</i>, <i>`-INF`</i>, and <i>`NaN`</i>. You can check a value for plus
1390 or minus infinity and not-a-number as follows:
1391 
1392 ~~~{.cpp}
1393  soap_isinf(x) && x > 0 // is x INF?
1394  soap_isinf(x) && x < 0 // is x -INF?
1395  soap_isnan(x) // is x NaN?
1396 ~~~
1397 
1398 To assign these values, use:
1399 
1400 ~~~{.cpp}
1401  // x is float // x is double, long double, or __float128
1402  x = FLT_PINFY; x = DBL_PINFTY;
1403  x = FLT_NINFY; x = DBL_NINFTY;
1404  x = FLT_NAN; x = DBL_NAN;
1405 ~~~
1406 
1407 If your system supports `__float128` then you can also use this 128 bit
1408 floating point type with a custom serializer:
1409 
1410 ~~~{.cpp}
1411  #import "custom/float128.h"
1412  ... // use xsd__decimal
1413 ~~~
1414 
1415 Then use the `xsd__decimal` alias of `__float128`, which has a serializer. Do
1416 not use `__float128` directly, which is transient (not serializable).
1417 
1418 To check for <i>`INF`</i>, <i>`-INF`</i>, and <i>`NaN`</i> of a `__float128`
1419 value use:
1420 
1421 ~~~{.cpp}
1422  isinfq(x) && x > 0 // is x INF?
1423  isinfq(x) && x < 0 // is x -INF?
1424  isnanq(x) // is x NaN?
1425 ~~~
1426 
1427 The range of a `typedef`-defined numerical type can be restricted using the range
1428 `:` operator with inclusive lower and upper bounds. For example:
1429 
1430 ~~~{.cpp}
1431  typedef int ns__narrow -10 : 10;
1432 ~~~
1433 
1434 This maps to a simpleType restriction of <i>`xsd:int`</i> in the soapcpp2-generated
1435 schema:
1436 
1437 <div class="alt">
1438 ~~~{.xml}
1439  <simpleType name="narrow">
1440  <restriction base="xsd:int">
1441  <minInclusive value="-10"/>
1442  <maxInclusive value="10"/>
1443  </restriction>
1444  </simpleType>
1445 ~~~
1446 </div>
1447 
1448 The lower and upper bound of a range are optional. When omitted, values are
1449 not bound from below or from above, respectively.
1450 
1451 The range of a floating point `typedef`-defined type can be restricted within
1452 floating point constant bounds.
1453 
1454 Also with a floating point `typedef` a `printf`-format pattern can be given of the
1455 form `"%[width][.precision]f"` to format decimal values using the given width
1456 and precision fields:
1457 
1458 ~~~{.cpp}
1459  typedef float ns__PH "%5.2f" 0.0 : 14.0;
1460 ~~~
1461 
1462 This maps to a simpleType restriction of <i>`xsd:float`</i> in the soapcpp2-generated
1463 schema:
1464 
1465 <div class="alt">
1466 ~~~{.xml}
1467  <simpleType name="PH">
1468  <restriction base="xsd:float">
1469  <totalDigits value="5"/>
1470  <fractionDigits value="2"/>
1471  <minInclusive value="0"/>
1472  <maxInclusive value="14"/>
1473  </restriction>
1474  </simpleType>
1475 ~~~
1476 </div>
1477 
1478 For exclusive bounds, we use the `<` operator instead of the `:` range
1479 operator:
1480 
1481 ~~~{.cpp}
1482  typedef float ns__epsilon 0.0 < 1.0;
1483 ~~~
1484 
1485 Values `eps` of `ns__epsilon` are restricted between `0.0 < eps < 1.0`.
1486 
1487 This maps to a simpleType restriction of <i>`xsd:float`</i> in the soapcpp2-generated
1488 schema:
1489 
1490 <div class="alt">
1491 ~~~{.xml}
1492  <simpleType name="epsilon">
1493  <restriction base="xsd:float">
1494  <minExclusive value="0"/>
1495  <maxExclusive value="1"/>
1496  </restriction>
1497  </simpleType>
1498 ~~~
1499 </div>
1500 
1501 To make just one of the bounds exclusive, while keeping the other bound
1502 inclusive, we add a `<` on the left or on the right side of the range ':'
1503 operator. For example:
1504 
1505 ~~~{.cpp}
1506  typedef float ns__pos 0.0 < : ; // 0.0 < pos
1507  typedef float ns__neg : < 0.0 ; // neg < 0.0
1508 ~~~
1509 
1510 It is valid to make both left and right side exclusive with `< : <` which is in
1511 fact identical to the exlusive range `<` operator:
1512 
1513 ~~~{.cpp}
1514  typedef float ns__epsilon 0.0 < : < 1.0; // 0.0 < eps < 1.0
1515 ~~~
1516 
1517 It helps to think of the `:` as a placeholder of the value between the two
1518 bounds, which is easier to memorize than the shorthand forms of bounds from
1519 which the `:` is removed:
1520 
1521 | bounds | validation check | shorthand |
1522 | ------------ | ---------------- | ----------- |
1523 | `1 : ` | 1 <= x | `1 ` |
1524 | `1 : 10 ` | 1 <= x <= 10 | |
1525 | ` : 10 ` | x <= 10 | |
1526 | `1 < : < 10` | 1 < x < 10 | `1 < 10 ` |
1527 | `1 : < 10` | 1 <= x < 10 | |
1528 | ` : < 10` | x < 10 | ` < 10 ` |
1529 | `1 < : ` | 1 < x | `1 < ` |
1530 | `1 < : 10 ` | 1 < x <= 10 | |
1531 
1532 Besides `float`, also `double` and `long double` values can be restricted. For
1533 example, consider a nonzero probability extended floating point precision type:
1534 
1535 ~~~{.cpp}
1536  #import "custom/long_double.h"
1537  typedef long double ns__probability "%16Lg" 0.0 < : 1.0;
1538 ~~~
1539 
1540 Value range restrictions are validated by the parser for all inbound XML data.
1541 A type fault `SOAP_TYPE` will be thrown by the deserializer if the value is out
1542 of range.
1543 
1544 Finally, if your system supports `__int128_t` then you can also use this 128
1545 bit integer type with a custom serializer:
1546 
1547 ~~~{.cpp}
1548  #import "custom/int128.h"
1549  ... // use xsd__integer
1550 ~~~
1551 
1552 Use the `xsd__integer` alias of `__int128_t`, which has a serializer. Do not
1553 use `__int128_t` directly, which is transient (not serializable).
1554 
1555 To convert numeric values to a string, we use the auto-generated function for
1556 numeric type `T`:
1557 
1558 ~~~{.cpp}
1559  const char *soap_T2s(struct soap*, T val)
1560 ~~~
1561 
1562 For numeric types `T`, the string returned is stored in an internal buffer of
1563 the current `soap` context, so you should copy it to keep it from being
1564 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1565 
1566 To convert a string to a numeric value, we use the auto-generated function
1567 
1568 ~~~{.cpp}
1569  int soap_s2T(struct soap*, const char *str, T *val)
1570 ~~~
1571 
1572 where `T` is for example `int`, `LONG64`, `float`, `decimal` (the custom
1573 serializer name of `long double`) or `xsd__integer` (the custom serializer name
1574 of `__int128_t`). The function `soap_s2T` returns `SOAP_OK` on success or an
1575 error when the value is not numeric. For floating point types, `"INF"`, `"-INF"`
1576 and `"NaN"` are valid strings to convert to numbers.
1577 
1578 🔝 [Back to table of contents](#)
1579 
1580 String types {#toxsd6}
1581 ------------
1582 
1583 String types are mapped to the built-in <i>`xsd:string`</i> and <i>`xsd:QName`</i> XSD types.
1584 
1585 The wide strings `wchar_t*` and `std::wstring` may contain Unicode that is
1586 preserved in the XML value space.
1587 
1588 Strings `char*` and `std::string` can only contain extended Latin, but we can
1589 store UTF-8 content that is preserved in the XML value space when the `soap`
1590 context is initialized with the flag `SOAP_C_UTFSTRING`.
1591 
1592 @warning Beware that many XML 1.0 parsers reject all control characters (those
1593 between `#x1` and `#x1F`) except for `#x9`, `#xA`, and `#xD`. With the
1594 newer XML 1.1 version parsers (including gSOAP) you should be fine.
1595 
1596 The length of a string of a `typedef`-defined string type can be restricted:
1597 
1598 ~~~{.cpp}
1599  typedef std::string ns__password 6 : 16;
1600 ~~~
1601 
1602 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1603 schema:
1604 
1605 <div class="alt">
1606 ~~~{.xml}
1607  <simpleType name="password">
1608  <restriction base="xsd:string">
1609  <minLength value="6"/>
1610  <maxLength value="16"/>
1611  </restriction>
1612  </simpleType>
1613 ~~~
1614 </div>
1615 
1616 String length restrictions are validated by the parser for inbound XML data.
1617 A value length fault `SOAP_LENGTH` will be thrown by the deserializer if the
1618 string is too long or too short.
1619 
1620 In addition, an XSD regex pattern restriction can be associated with a string
1621 typedef:
1622 
1623 ~~~{.cpp}
1624  typedef std::string ns__password "([a-zA-Z]|[0-9]|-)+" 6 : 16;
1625 ~~~
1626 
1627 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1628 schema:
1629 
1630 <div class="alt">
1631 ~~~{.xml}
1632  <simpleType name="password">
1633  <restriction base="xsd:string">
1634  <pattern value="([a-zA-Z0-9]|-)+"/>
1635  <minLength value="6"/>
1636  <maxLength value="16"/>
1637  </restriction>
1638  </simpleType>
1639 ~~~
1640 </div>
1641 
1642 Pattern restrictions are validated by the parser for inbound XML data only if
1643 the `soap::fsvalidate` and `soap::fwvalidate` callbacks are defined.
1644 
1645 Exclusive length bounds can be used with strings:
1646 
1647 ~~~{.cpp}
1648  typedef std::string ns__string255 : < 256; // same as 0 : 255
1649 ~~~
1650 
1651 Fixed-size strings (`char[N]`) are rare occurrences in the wild, but apparently
1652 still used in some projects to store strings. To facilitate fixed-size string
1653 serialization, use <b>`soapcpp2 -b`</b> option <b>`-b`</b>. For example:
1654 
1655 ~~~{.cpp}
1656  typedef char ns__buffer[10]; // requires soapcpp2 option -b
1657 ~~~
1658 
1659 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1660 schema:
1661 
1662 <div class="alt">
1663 ~~~{.xml}
1664  <simpleType name="buffer">
1665  <restriction base="xsd:string">
1666  <maxLength value="9"/>
1667  </restriction>
1668  </simpleType>
1669 ~~~
1670 </div>
1671 
1672 Fixed-size strings must contain NUL-terminated text and should not contain raw
1673 binary data. Also, the length limitation is more restrictive for UTF-8 content
1674 (enabled with the `SOAP_C_UTFSTRING`) that requires multibyte character
1675 encodings. As a consequence, UTF-8 content may be truncated to fit.
1676 
1677 Raw binary data can be stored in a `xsd__base64Binary` or `xsd__hexBinary`
1678 structure, or transmitted as a MIME attachment.
1679 
1680 The built-in `_QName` type is a regular C string type (`char*`) that maps to
1681 <i>`xsd:QName`</i> but has the added advantage that it holds normalized qualified names.
1682 There are actually two forms of normalized QName content, to ensure any QName
1683 is represented accurately:
1684 
1685 ~~~{.cpp}
1686  "prefix:name"
1687  "\"URI\":name"
1688 ~~~
1689 
1690 The first form of string is used when the prefix (and the binding URI) is
1691 defined in the namespace table and is bound to a URI (see the .nsmap file).
1692 The second form is used when the URI is not defined in the namespace table and
1693 therefore no prefix is available to bind and normalize the URI to.
1694 
1695 A `_QName` string may contain a sequence of space-separated QName values, not
1696 just one, and all QName values are normalized to the format shown above.
1697 
1698 To define a `std::string` base type for <i>`xsd:QName`</i>, we use a `typedef`:
1699 
1700 ~~~{.cpp}
1701  typedef std::string xsd__QName;
1702 ~~~
1703 
1704 The `xsd__QName` string content is normalized, just as with the `_QName`
1705 normalization.
1706 
1707 To serialize strings that contain literal XML content to be reproduced in the
1708 XML value space, use the built-in `_XML` string type, which is a regular C
1709 string type (`char*`) that maps to plain XML CDATA.
1710 
1711 To define a `std::string` base type for literal XML content, use a `typedef`:
1712 
1713 ~~~{.cpp}
1714  typedef std::string XML;
1715 ~~~
1716 
1717 Strings can hold any of the values of the XSD built-in primitive types. We can
1718 use a string `typedef` to declare the use of the string type as a XSD built-in
1719 type:
1720 
1721 ~~~{.cpp}
1722  typedef std::string xsd__token;
1723 ~~~
1724 
1725 You must ensure that the string values we populate in this type conform to the
1726 XML standard, which in case of <i>`xsd:token`</i> is the lexical and value spaces of
1727 <i>`xsd:token`</i> are the sets of all strings after whitespace replacement of any
1728 occurrence of `#x9`, `#xA` , and `#xD` by `#x20` and collapsing.
1729 
1730 As of version 2.8.49, the gSOAP parser will automatically collapse or replace
1731 the white space content when receiving data for XSD types that require white
1732 space collapsed or replaced. This normalization is applied to strings
1733 directly. The decision to collapse or replace is based on the `typedef` name
1734 corresponding to the built-in string-based XSD type.
1735 
1736 To copy `char*` or `wchar_t*` strings with a context that manages the allocated
1737 memory, use functions
1738 
1739 ~~~{.cpp}
1740  char *soap_strdup(struct soap*, const char*)
1741  wchar_t *soap_wstrdup(struct soap*, const wchar_t*)
1742 ~~~
1743 
1744 To convert a wide string to a UTF-8 encoded string, use function
1745 
1746 ~~~{.cpp}
1747  const char* SOAP_FMAC2 soap_wchar2s(struct soap*, const wchar_t *s)
1748 ~~~
1749 
1750 The function allocates and returns a string, with its memory being managed by
1751 the context.
1752 
1753 To convert a UTF-8 encoded string to a wide string, use function
1754 
1755 ~~~{.cpp}
1756  int soap_s2wchar(struct soap*, const char *from, wchar_t **to, long minlen, long maxlen)
1757 ~~~
1758 
1759 where `to` is set to point to an allocated `wchar_t*` string. Pass `-1` for
1760 `minlen` and `maxlen` to ignore length constraints on the target string. The
1761 function returns `SOAP_OK` or an error when the length constraints are not met.
1762 
1763 🔝 [Back to table of contents](#)
1764 
1765 Date and time types {#toxsd7}
1766 -------------------
1767 
1768 The C/C++ `time_t` type is mapped to the built-in <i>`xsd:dateTime`</i> XSD type that
1769 represents a date and time within a time zone (typically UTC).
1770 
1771 The XML value space contains ISO 8601 Gregorian time instances of the form
1772 <i>`[-]CCYY-MM-DDThh:mm:ss.sss[Z|(+|-)hh:mm]`</i>, where <i>`Z`</i> is the UTC time zone
1773 or a time zone offset <i>`(+|-)hh:mm]`</i> from UTC is used.
1774 
1775 A `time_t` value is considered and represented in UTC by the serializer.
1776 
1777 Because the `time_t` value range is restricted to dates after 01/01/1970 and
1778 before 2038 assuming `time_t` is a `long` 32 bit, care must be taken to ensure
1779 the range of <i>`xsd:dateTime`</i> values in XML exchanges do not exceed the `time_t`
1780 range.
1781 
1782 This restriction does not hold for `struct tm` (<i>`time.h`</i> library), which we can use
1783 to store and exchange a date and time in UTC without date range restrictions.
1784 The serializer uses the `struct tm` members directly for the XML value space of
1785 <i>`xsd:dateTime`</i>:
1786 
1787 ~~~{.cpp}
1788  struct tm
1789  {
1790  int tm_sec; // seconds (0 - 60)
1791  int tm_min; // minutes (0 - 59)
1792  int tm_hour; // hours (0 - 23)
1793  int tm_mday; // day of month (1 - 31)
1794  int tm_mon; // month of year (0 - 11)
1795  int tm_year; // year - 1900
1796  int tm_wday; // day of week (Sunday = 0) (NOT USED)
1797  int tm_yday; // day of year (0 - 365) (NOT USED)
1798  int tm_isdst; // is summer time in effect?
1799  char* tm_zone; // abbreviation of timezone (NOT USED)
1800  };
1801 ~~~
1802 
1803 You will lose the day of the week information. It is always Sunday
1804 (`tm_wday=0`) and the day of the year is not set either. The time zone is UTC.
1805 
1806 This `struct tm` type is mapped to the built-in <i>`xsd:dateTime`</i> XSD type and
1807 serialized with the custom serializer <i>`gsoap/custom/struct_tm.h`</i> that declares a
1808 `xsd__dateTime` type:
1809 
1810 ~~~{.cpp}
1811  #import "custom/struct_tm.h" // import typedef struct tm xsd__dateTime;
1812  ... // use xsd__dateTime
1813 ~~~
1814 
1815 Compile and link your code with <i>`gsoap/custom/struct_tm.c`</i>.
1816 
1817 The `struct timeval` (<i>`sys/time.h`</i> library) type is mapped to the
1818 built-in <i>`xsd:dateTime`</i> XSD type and serialized with the custom serializer
1819 <i>`gsoap/custom/struct_timeval.h`</i> that declares a `xsd__dateTime` type:
1820 
1821 ~~~{.cpp}
1822  #import "custom/struct_timeval.h" // import typedef struct timeval xsd__dateTime;
1823  ... // use xsd__dateTime
1824 ~~~
1825 
1826 Compile and link your code with <i>`gsoap/custom/struct_timeval.c`</i>.
1827 
1828 The same value range restrictions apply to `struct timeval` as they apply to
1829 `time_t`. The added benefit of `struct timeval` is the addition of a
1830 microsecond-precise clock:
1831 
1832 ~~~{.cpp}
1833  struct timeval
1834  {
1835  time_t tv_sec; // seconds since Jan. 1, 1970
1836  suseconds_t tv_usec; // and microseconds
1837  };
1838 ~~~
1839 
1840 A C++11 `std::chrono::system_clock::time_point` type is mapped to the built-in
1841 <i>`xsd:dateTime`</i> XSD type and serialized with the custom serializer
1842 <i>`gsoap/custom/chrono_time_point.h`</i> that declares a `xsd__dateTime` type:
1843 
1844 ~~~{.cpp}
1845  #import "custom/chrono_time_point.h" // import typedef std::chrono::system_clock::time_point xsd__dateTime;
1846  ... // use xsd__dateTime
1847 ~~~
1848 
1849 Compile and link your code with <i>`gsoap/custom/chrono_time_point.cpp`</i>.
1850 
1851 The `struct tm` type is mapped to the built-in <i>`xsd:date`</i> XSD type and serialized
1852 with the custom serializer <i>`gsoap/custom/struct_tm_date.h`</i> that declares a
1853 `xsd__date` type:
1854 
1855 ~~~{.cpp}
1856  #import "custom/struct_tm_date.h" // import typedef struct tm xsd__date;
1857  ... // use xsd__date
1858 ~~~
1859 
1860 Compile and link your code with <i>`gsoap/custom/struct_tm_date.c`</i>.
1861 
1862 The XML value space of <i>`xsd:date`</i> are Gregorian calendar dates of the form
1863 <i>`[-]CCYY-MM-DD[Z|(+|-)hh:mm]`</i> with a time zone.
1864 
1865 The serializer ignores the time part and the deserializer only populates the
1866 date part of the struct, setting the time to 00:00:00. There is no unreasonable
1867 limit on the date range because the year field is stored as an integer (`int`).
1868 
1869 An `unsigned long long` (`ULONG64` or `uint64_t`) type that contains a 24 hour
1870 time in microseconds UTC is mapped to the built-in <i>`xsd:time`</i> XSD type and
1871 serialized with the custom serializer <i>`gsoap/custom/long_time.h`</i> that declares a
1872 `xsd__time` type:
1873 
1874 ~~~{.cpp}
1875  #import "custom/long_time.h" // import typedef unsigned long long xsd__time;
1876  ... // use xsd__time
1877 ~~~
1878 
1879 Compile and link your code with <i>`gsoap/custom/long_time.c`</i>.
1880 
1881 This type represents `00:00:00.000000` to `23:59:59.999999`, from 0 to an
1882 upper bound of 86,399,999,999. A microsecond resolution means that a 1 second
1883 increment requires an increment of 1,000,000 in the integer value.
1884 
1885 The XML value space of <i>`xsd:time`</i> are points in time recurring each day of the
1886 form <i>`hh:mm:ss.sss[Z|(+|-)hh:mm]`</i>, where <i>`Z`</i> is the UTC time zone or a time
1887 zone offset from UTC is used. The `xsd__time` value is always considered and
1888 represented in UTC by the serializer.
1889 
1890 To convert date and/or time values to a string, we use the auto-generated
1891 function for type `T`:
1892 
1893 ~~~{.cpp}
1894  const char *soap_T2s(struct soap*, T val)
1895 ~~~
1896 
1897 For date and time types `T`, the string returned is stored in an internal
1898 buffer of the current `soap` context, so you should copy it to keep it from being
1899 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1900 
1901 To convert a string to a date/time value, we use the auto-generated function
1902 
1903 ~~~{.cpp}
1904  int soap_s2T(struct soap*, const char *str, T *val)
1905 ~~~
1906 
1907 where `T` is for example `dateTime` (for `time_t`), `xsd__dateTime` (for
1908 `struct tm`, `struct timeval`, or `std::chrono::system_clock::time_point`).
1909 The function `soap_s2T` returns `SOAP_OK` on success or an error when the value
1910 is not a date/time.
1911 
1912 🔝 [Back to table of contents](#)
1913 
1914 Time duration types {#toxsd8}
1915 -------------------
1916 
1917 The XML value space of <i>`xsd:duration`</i> are values of the form <i>`PnYnMnDTnHnMnS`</i>
1918 where the capital letters are delimiters. Delimiters may be omitted when the
1919 corresponding member is not used.
1920 
1921 A `long long` (`LONG64` or `int64_t`) type that contains a duration (time
1922 lapse) in milliseconds is mapped to the built-in <i>`xsd:duration`</i> XSD type and
1923 serialized with the custom serializer <i>`gsoap/custom/duration.h`</i> that declares a
1924 `xsd__duration` type:
1925 
1926 ~~~{.cpp}
1927  #import "custom/duration.h" // import typedef long long xsd__duration;
1928  ... // use xsd__duration
1929 ~~~
1930 
1931 Compile and link your code with <i>`gsoap/custom/duration.c`</i>.
1932 
1933 The duration type `xsd__duration` can represent 106,751,991,167 days forward
1934 and backward with millisecond precision.
1935 
1936 Durations that exceed a month are always output in days, rather than months to
1937 avoid days-per-month conversion inacurracies.
1938 
1939 Durations that are received in years and months instead of total number of days
1940 from a reference point are not well defined, since there is no accepted
1941 reference time point (it may or may not be the current time). The decoder
1942 simple assumes that there are 30 days per month. For example, conversion of
1943 "P4M" gives 120 days. Therefore, the durations "P4M" and "P120D" are assumed
1944 to be identical, which is not necessarily true depending on the reference point
1945 in time.
1946 
1947 Rescaling of the duration value by may be needed when adding the duration value
1948 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
1949 depending on the platform and possible changes to `time_t`.
1950 
1951 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
1952 value to a `std::chrono::system_clock::time_point` value. To use
1953 `std::chrono::nanoseconds` as <i>`xsd:duration`</i>:
1954 
1955 ~~~{.cpp}
1956  #import "custom/chrono_duration.h" // import typedef std::chrono::duration xsd__duration;
1957  ... // use xsd__duration
1958 ~~~
1959 
1960 Compile and link your code with <i>`gsoap/custom/chrono_duration.cpp`</i>.
1961 
1962 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
1963 backwards in time in increments of 1 ns (1/1000000000 second).
1964 
1965 The same observations with respect to receiving durations in years and months
1966 apply to this serializer's decoder.
1967 
1968 To convert duration values to a string, we use the auto-generated function
1969 
1970 ~~~{.cpp}
1971  const char *soap_xsd__duration2s(struct soap*, xsd__duration val)
1972 ~~~
1973 
1974 The string returned is stored in an internal buffer, so you should copy it to
1975 keep it from being overwritten, Use `soap_strdup(struct soap*, const char*)`
1976 for example to copy this string.
1977 
1978 To convert a string to a duration value, we use the auto-generated function
1979 
1980 ~~~{.cpp}
1981  int soap_s2xsd__dateTime(struct soap*, const char *str, xsd__dateTime *val)
1982 ~~~
1983 
1984 The function returns `SOAP_OK` on success or an error when the value is not a
1985 duration.
1986 
1987 🔝 [Back to table of contents](#)
1988 
1989 Classes and structs {#toxsd9}
1990 -------------------
1991 
1992 Classes and structs are mapped to XSD complexTypes. The XML value space
1993 consists of XML elements with attributes and subelements, possibly constrained
1994 by XML schema validation rules that enforce element and attribute occurrence
1995 contraints, numerical value range constraints, and string length and pattern
1996 constraints.
1997 
1998 Classes that are declared with the gSOAP tools are limited to single
1999 inheritence only. The soapcpp2 tool does not allow structs to be inherited.
2000 
2001 The class and struct name is bound to an XML namespace by means of the prefix
2002 naming convention or by using [colon notation](#toxsd1):
2003 
2004 ~~~{.cpp}
2005  //gsoap ns schema namespace: urn:types
2006  class ns__record
2007  {
2008  public:
2009  std::string name;
2010  uint64_t SSN;
2011  ns__record *spouse;
2012  ns__record();
2013  ~ns__record();
2014  protected:
2015  struct soap *soap;
2016  };
2017 ~~~
2018 
2019 In the example above, we also added a context pointer to the `soap` context that
2020 manages this instance. It is set when the instance is created in the engine's
2021 context, for example when deserialized and populated by the engine.
2022 
2023 The class maps to a complexType in the soapcpp2-generated XML schema:
2024 
2025 <div class="alt">
2026 ~~~{.xml}
2027  <complexType name="record">
2028  <sequence>
2029  <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2030  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
2031  <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
2032  </sequence>
2033  </complexType>
2034 ~~~
2035 </div>
2036 
2037 The following sections apply to both structs and classes. Structs require the
2038 use of the `struct` keyword with the struct name, otherwise soapcpp2 will throw
2039 a syntax error. As is often done in C, use a `typedef` to declare a `struct`
2040 that can be used without the `struct` keyword.
2041 
2042 🔝 [Back to table of contents](#)
2043 
2044 ### Serializable versus transient types and data members {#toxsd9-1}
2045 
2046 Public data members of a class or struct are serializable when their types are
2047 serializable. Private and protected members are transient and not
2048 serializable.
2049 
2050 Also `const` and `static` members are not serializable, with the exception of
2051 `const char*` and `const wchar_t*`. Types and specific class/struct members
2052 can be made transient with the `extern` qualifier for types and by marking
2053 members with `[` and `]`:
2054 
2055 ~~~{.cpp}
2056  extern class std::ostream; // declare std::ostream transient
2057  class ns__record
2058  {
2059  public:
2060  [ int num; ] // not serialized: member is marked transient with [ ]
2061  std::ostream out; // not serialized: std:ostream is transient
2062  static const int MAX = 1024; // not serialized: static const member
2063  private:
2064  std::string id; // not serialized: private member
2065  };
2066 ~~~
2067 
2068 By declaring `std::ostream` transient with `extern` you can use this type
2069 wherever you need it without soapcpp2 complaining that this class and any other
2070 class or type declared as `extern` is not defined. Do not use `extern` with
2071 `typedef`, because this declares a custom serializer, see
2072 [adding custom serializers](#custom).
2073 
2074 Marking members transient with `[` and `]` makes them transient (and visually
2075 makes them stand out). This has otherwise no effect on the generated code for
2076 the class or struct to be used in your application code.
2077 
2078 🔝 [Back to table of contents](#)
2079 
2080 ### Derived types in C++ {#toxsd9-1-1}
2081 
2082 Extensible and restricted types in XML schemas are derived types from single
2083 simple and complex base types. XML schema derived types are naturally
2084 represented by C++ derived classes using single inheritance. Besides the
2085 concept of extensions versus restrictions, there are two kinds of derived
2086 types: complexTypes with simpleContent, meaning types with XML CDATA values,
2087 and complexTypes with complexContent, meaning types with sub-elements. Both
2088 are permitted to have one or more XML attributes.
2089 
2090 A complexType with simpleContent is defined as a wrapper to contain XML CDATA
2091 values and any number of attributes, see
2092 [wrapper class/struct with simpleContent](#toxsd10-4).
2093 Wrapper class/struct types can form a hierarchy of derived types in C++ using
2094 inheritance. For example:
2095 
2096 ~~~{.cpp}
2097  class xsd__anyType
2098  {
2099  public:
2100  std::string __item; // string to hold any simpleContent
2101  };
2102  class ns__data : public xsd__anyType
2103  {
2104  public:
2105  @ std::string value 1; // extends xsd:anyType with a required attribute
2106  };
2107 ~~~
2108 
2109 The `ns__data` class maps to a complexType in the soapcpp2-generated XML schema:
2110 
2111 <div class="alt">
2112 ~~~{.xml}
2113  <complexType name="string">
2114  <simpleContent>
2115  <extension base="xsd:string">
2116  <attribute name="value" type="xsd:string" use="required"/>
2117  </extension>
2118  </simpleContent>
2119  </complexType>
2120 ~~~
2121 </div>
2122 
2123 The XML value space consists of an element with the string contents an optional
2124 attribute:
2125 
2126 <div class="alt">
2127 ~~~{.xml}
2128  <ns:data value="abc">xyz</ns:data>
2129 ~~~
2130 </div>
2131 
2132 By contrast, a complexType with complexContent typically extends a given base
2133 complexType. For example:
2134 
2135 ~~~{.cpp}
2136  class ns__base
2137  {
2138  public:
2139  std::string name 1;
2140  int number 1;
2141  };
2142  class ns__derived : public ns__base
2143  {
2144  public:
2145  @ std::string value 1; // extends ns:base with an attribute
2146  std::string text 1; // extends ns:base with an element
2147  };
2148 ~~~
2149 
2150 The `ns__base` and `ns__derived` classes maps to complexTypes in the soapcpp2-generated XML schema:
2151 
2152 <div class="alt">
2153 ~~~{.xml}
2154  <complexType name="base">
2155  <sequence>
2156  <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2157  <element name="number" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2158  </sequence>
2159  </complexType>
2160  <complexType name="derived">
2161  <complexContent>
2162  <extension base="ns:base">
2163  <sequence>
2164  <element name="text" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2165  </sequence>
2166  </extension>
2167  </complexContent>
2168  <attribute name="value" type="xsd:string" use="required"/>
2169  </complexType>
2170 ~~~
2171 </div>
2172 
2173 The XML value space of `ns__derived` consists of three requires child elements
2174 and an optional attribute:
2175 
2176 <div class="alt">
2177 ~~~{.xml}
2178  <ns:derived value="abc">
2179  <name>def</name>
2180  <number>123</number>
2181  <text>xyz</text>
2182  </ns:derived>
2183 ~~~
2184 </div>
2185 
2186 Derived types can be used for two main purposes in XML schema by extending or
2187 restricting base types. One purpose is to reuse a base type when defining a
2188 derived type, such that common parts do not need to be replicated. The second
2189 purpose is to be able to use a derived type in place of a base type in XML, which
2190 is indicated by an <i>`xsi:type`</i> attribute with the qualified name of the
2191 derived type. Consider for example the following class that uses the
2192 previously declared base types `xsd__anyType` and `ns__base`:
2193 
2194 ~~~{.cpp}
2195  class ns__record
2196  {
2197  public:
2198  xsd__anyType *base1 1; // required element
2199  ns__base *base2 1; // required element
2200  };
2201 ~~~
2202 
2203 We can assign base type values to the `ns_record` members:
2204 
2205 ~~~{.cpp}
2206  ns__record record;
2207  record.base1 = soap_new_xsd__anyType(soap);
2208  record.base2 = soap_new_ns__base(soap);
2209  soap_write_ns__record(soap, &record);
2210 ~~~
2211 
2212 This produces the following XML fragment populated with default values (empty
2213 text for strings and zeros for numbers), where element <i>`base1`</i> has a
2214 simpleContent value and element <i>`base2`</i> has two child elements:
2215 
2216 <div class="alt">
2217 ~~~{.xml}
2218  <ns:record>
2219  <base1></base1>
2220  <base2>
2221  <name></name>
2222  <number>0</number>
2223  </base2>
2224  </ns:record>
2225 ~~~
2226 </div>
2227 
2228 We can also assign derived type values to the `ns_record` members:
2229 
2230 ~~~{.cpp}
2231  ns__record record;
2232  record.base1 = soap_new_ns__data(soap);
2233  record.base2 = soap_new_ns__derived(soap);
2234  soap_write_ns__record(soap, &record);
2235 ~~~
2236 
2237 This produces the following XML fragment populated with default values (empty
2238 text for strings and zeros for numbers), where element <i>`base1`</i> has
2239 schema type <i>`ns:data`</i> with simpleContent and an attribute, and
2240 <i>`base2`</i> has schema type <i>`ns:derived`</i> with three child elements
2241 and an attribute:
2242 
2243 <div class="alt">
2244 ~~~{.xml}
2245  <ns:record>
2246  <base1 xsi:type="ns:data" value=""></base1>
2247  <base2 xsi:type="ns:derived" value="">
2248  <name></name>
2249  <number>0</number>
2250  <text></text>
2251  </base2>
2252  </ns:record>
2253 ~~~
2254 </div>
2255 
2256 Deserialization automatically allocates and assigns a `ns__base` class instance to a
2257 `ns__base` pointer when deserializing the <i>`ns:base`</i> schema type and allocates and
2258 assigns a `ns__derived` class instance to a `ns__base` pointer when deserializing the
2259 <i>`ns:derived`</i> type when an element with <i>`xsi:type="ns:derived"`</i> is
2260 parsed. All classes are extended by soapcpp2 by a `soap_type()` method that
2261 returns the unique `SOAP_TYPE_T` value of the class `T`. This makes it easy to
2262 check whether the deserialized data contains a derived type to implement
2263 type-safe code, for example:
2264 
2265 ~~~{.cpp}
2266  ns__record record;
2267  soap_read_ns__record(soap, &record);
2268  if (record.base1->soap_type() == SOAP_TYPE_ns__data)
2269  std::cout << "Derived ns:data "
2270  << dynamic_cast<ns__data*>(record.base1)->value
2271  << std::endl;
2272  else
2273  std::cout << "Base xsd:anyType" << std::endl;
2274  if (record.base2->soap_type() == SOAP_TYPE_ns__derived)
2275  std::cout << "Derived ns:derived "
2276  << dynamic_cast<ns__derived*>(record.base2)->value
2277  << std::endl;
2278  else
2279  std::cout << "Base ns:base" << std::endl;
2280 ~~~
2281 
2282 This example should use the `SOAP_XML_STRICT` mode flag to initialize the
2283 `soap` context to ensure that all required values are present in the
2284 deserialized structures.
2285 
2286 🔝 [Back to table of contents](#)
2287 
2288 ### Derived types in C {#toxsd9-1-2}
2289 
2290 While single inheritance works well in C++ to represent derived types as we
2291 discussed in the previous section, this will obviously not work in C. Two
2292 methods to serialize derived types in C are presented here. The first method
2293 uses `void*` to serialize anything. The second method is more accurate and is
2294 relatively new in gSOAP.
2295 
2296 To serialize any type is possible with [tagged void pointer members](#toxsd9-12) to
2297 serialize data pointed to by a `void*` member, which can be any serializable
2298 type, such as derived types. For `void*` deserialization to work the XML
2299 parsed must contain an <i>`xsi:type`</i> attribute with a schema type. Only
2300 then can the deserializer instantiate the corresponding serializable C/C++
2301 type. Base types serialized do not require an <i>`xsi:type`</i> to indicate
2302 the base schema type, so this approach is not guaranteed to work and requires a
2303 workaround with an anonymous wrapper struct/class that contains both the base
2304 type and a `void*`. For example:
2305 
2306 ~~~{.cpp}
2307  struct ns__base // a base type
2308  {
2309  char *name 1;
2310  int number 1;
2311  };
2312  struct ns__derived // extends ns__base with two additional members
2313  {
2314  char *name 1;
2315  int number 1;
2316  char *text 1;
2317  @ char *value 1;
2318  };
2319  struct __ns__base // a wrapper, not visible in XML
2320  {
2321  int __type; // the SOAP_TYPE_T pointed to by __self
2322  void *__self; // points to any type
2323  struct ns__base *__self; // wraps ns__base for the current element tag
2324  }
2325  class ns__record
2326  {
2327  struct __ns__base base;
2328  };
2329 ~~~
2330 
2331 The `__ns__base` wrapper wraps the `ns__base` type to (de)serialize the
2332 <i>`base`</i> element that has no <i>`xsi:type`</i> attribute and uses `void*`
2333 to (de)serialize the <i>`base`</i> element that has <i>`xsi:type`</i>
2334 attribute. This works fine at the XML parsing level, but the generated
2335 XML schema components do not accurately represent the derived type, because it
2336 lacks the extension/restriction of the derived type (and the `__ns__base`
2337 wrapper is invisible).
2338 
2339 Using `void*` to represent derived types in a base type wrapper is not very
2340 accurate because we can serialize anything, not just derived types of a given
2341 base type. The wrapper may also hold two values: the base type value and a
2342 derived type value. Furthermore, using arrays or containers that hold base and
2343 derived types becomes quite tricky because an array item could hold both the
2344 base and derived type.
2345 
2346 As of gSOAP version 2.8.75, `wsdl2h -F` option `-F` generates base type structs
2347 extended with transient pointer members to its derived types. To serialize the
2348 base type itself, all of the pointer members are NULL. If one of the pointer
2349 members points to a derived type the derived type is serialized instead.
2350 Deserialization is automatic, in that the base type is deserialized if the
2351 element has no <i>`xsi:type`</i> attribute or the attribute is the base schema
2352 type, and a derived type is deserialized if the element has an
2353 <i>`xsi>type`</i> attribute with the derived schema type.
2354 
2355 This method is fully automated for the wsdl2h tool to generate an interface
2356 header file for soapcpp2 with the type derivations in C. To use this method to
2357 generate code from WSDLs and XSDs, use `wsdl2h -F` option `-F`. This also
2358 works in C++ if desired, but C++ inheritance works fine without this method.
2359 
2360 Using this method with soapcpp2 alone using a manually-specified interface
2361 header file produces the specified type inheritance in the soapcpp2-generated
2362 WSDL and XML schema files as complexType extensions.
2363 
2364 The soapcpp2 tool warns if a derived type has multiple base types. At most one
2365 base type for a derived type may be specified.
2366 
2367 This method with transient pointers to derived types makes it easy to use base
2368 and derived types in C:
2369 
2370 ~~~{.cpp}
2371  struct ns__base // a base type
2372  {
2373  char *name 1;
2374  int number 1;
2375  [ struct ns__derived *ns__derived; ] // points to derived type if non-NULL
2376  };
2377  struct ns__derived // extends ns__base with two additional members
2378  {
2379  char *name 1;
2380  int number 1;
2381  char *text 1;
2382  @ char *value 1;
2383  };
2384  struct ns__record
2385  {
2386  struct ns__base base; // contains base type or derived type value
2387  };
2388 ~~~
2389 
2390 The `ns__base` struct includes the special member `ns__derived` that points to
2391 a `ns__derived` value. This special member must be:
2392 
2393 - a transient member (i.e. non-serializable) by placing the declaration within
2394  `[` and `]`, and
2395 - the member name must match the type name (to be more precise, at least the
2396  initial part of the member name must match the type name as in the example
2397  `ns__derived_` works too).
2398 
2399 To serialize the `ns__base` value requires the `ns__derived` member to be NULL.
2400 To serialize the `ns__derived` value requires the `ns__derived` member to point
2401 to the `ns__derived` value to serialize and the `ns__base` members are
2402 irrelevant.
2403 
2404 We can assign the base type value to the `ns_record::base` member:
2405 
2406 ~~~{.cpp}
2407  struct ns__record record;
2408  soap_default_ns__record(soap, &record);
2409  soap_write_ns__record(soap, &record);
2410 ~~~
2411 
2412 This produces the following XML fragment populated with default values (empty
2413 text for strings and zeros for numbers), where element <i>`base`</i> has two
2414 child elements:
2415 
2416 <div class="alt">
2417 ~~~{.xml}
2418  <ns:record>
2419  <base>
2420  <name></name>
2421  <number>0</number>
2422  </base>
2423  </ns:record>
2424 ~~~
2425 </div>
2426 
2427 We can also assign the derived type value to the `ns_record::base` member:
2428 
2429 ~~~{.cpp}
2430  struct ns__record record;
2431  soap_default_ns__record(soap, &record);
2432  record.base.ns__derived = soap_new_ns__derived(soap, -1);
2433  soap_write_ns__record(soap, &record);
2434 ~~~
2435 
2436 This produces the following XML fragment populated with default values (empty
2437 text for strings and zeros for numbers), where element <i>`base`</i> has schema
2438 type <i>`ns:derived`</i> with three child elements and an attribute:
2439 
2440 <div class="alt">
2441 ~~~{.xml}
2442  <ns:record>
2443  <base xsi:type="ns:derived" value="">
2444  <name></name>
2445  <number>0</number>
2446  <text></text>
2447  </base>
2448  </ns:record>
2449 ~~~
2450 </div>
2451 
2452 Deserialization automatically assigns values to the base members for the
2453 `ns__base` type and populates the `ns__derived` member when a derived type with
2454 <i>`xsi:type="ns:derived"`</i> is parsed. This makes it easy to decompose the
2455 deserialized data:
2456 
2457 ~~~{.cpp}
2458  struct ns__record record;
2459  soap_read_ns__record(soap, &record);
2460  if (record.ns__derived)
2461  printf("Derived type with name=%s number=%d text=%s value=%s\n",
2462  record.ns__derived->name,
2463  record.ns__derived->number,
2464  record.ns__derived->text,
2465  record.ns__derived->value);
2466  else
2467  printf("Base type with name=%s number=%d\n",
2468  record.name,
2469  record.number);
2470 ~~~
2471 
2472 This example requires the `SOAP_XML_STRICT` mode flag to initialize the `soap`
2473 context to ensure that all required values are present in the deserialized
2474 structures, otherwise the `char*` strings may be NULL since XML validation
2475 constraints are not enforced on the XML input.
2476 
2477 Deeper levels of simulated inheritance are possible, for example:
2478 
2479 ~~~{.cpp}
2480  struct ns__base // a base type
2481  {
2482  char *name 1;
2483  int number 1;
2484  [ struct ns__derived *ns__derived; ] // points to derived type if non-NULL
2485  };
2486  struct ns__derived // extends ns__base with two additional members
2487  {
2488  char *name 1;
2489  int number 1;
2490  char *text 1;
2491  @ char *value 1;
2492  [ struct ns__derived_derived *ns__derived_derived; ] // points to derived_derived type if non-NULL
2493  };
2494  struct ns__derived_derived // extends ns__derived with an additional member
2495  {
2496  char *name 1;
2497  int number 1;
2498  char *text 1;
2499  @ char *value 1;
2500  @ char *type 1;
2501  };
2502 ~~~
2503 
2504 This requires two pointer traversals from the base type `ns__base` via
2505 `ns__derived` to reach `ns__derived_derived`.
2506 
2507 🔝 [Back to table of contents](#)
2508 
2509 ### Volatile classes and structs {#toxsd9-2}
2510 
2511 Classes and structs can be declared `volatile` in the interface header file for
2512 soapcpp2, which only has meaning for the gSOAP tools. This annotation means
2513 that these types are already declared elsewhere in your project's source code
2514 and you do not want soapcpp2 to generate code with a second declaration of
2515 these types.
2516 
2517 For example, `struct tm` is declared in the <i>`time.h`</i> library. You can
2518 make it serializable and include a partial list of data members that you want
2519 to serialize:
2520 
2521 ~~~{.cpp}
2522  volatile struct tm
2523  {
2524  int tm_sec; // seconds (0 - 60)
2525  int tm_min; // minutes (0 - 59)
2526  int tm_hour; // hours (0 - 23)
2527  int tm_mday; // day of month (1 - 31)
2528  int tm_mon; // month of year (0 - 11)
2529  int tm_year; // year - 1900
2530  };
2531 ~~~
2532 
2533 You can declare classes and structs `volatile` for any such types you want to
2534 serialize by only providing the public data members you want to serialize.
2535 
2536 In addition, [colon notation](#toxsd2) is a simple and effective way to bind an
2537 existing class or struct to a schema. For example, you can change the `tm` name
2538 as follows without affecting the code that uses `struct tm` generated by
2539 soapcpp2:
2540 
2541 ~~~{.cpp}
2542  volatile struct ns:tm { ... }
2543 ~~~
2544 
2545 This struct maps to a complexType in the soapcpp2-generated XML schema:
2546 
2547 <div class="alt">
2548 ~~~{.xml}
2549  <complexType name="tm">
2550  <sequence>
2551  <element name="tm-sec" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2552  <element name="tm-min" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2553  <element name="tm-hour" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2554  <element name="tm-mday" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2555  <element name="tm-mon" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2556  <element name="tm-year" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2557  </sequence>
2558  </complexType>
2559 ~~~
2560 </div>
2561 
2562 🔝 [Back to table of contents](#)
2563 
2564 ### Mutable classes and structs {#toxsd9-3}
2565 
2566 Classes and structs can be declared `mutable` with the gSOAP tools. This means
2567 that their definition can be spread out over the source code. This promotes the
2568 concept of a class or struct as a *row of named values*, also known as a *named
2569 tuple*, that can be extended at compile time in your source code with additional
2570 members. Because these types differ from the traditional object-oriented
2571 principles and design concepts of classes and objects, constructors and
2572 destructors cannot be defined (also because we cannot guarantee merging these
2573 into one such that all members will be initialized). A default constructor,
2574 copy constructor, assignment operation, and destructor will be assigned
2575 automatically by soapcpp2.
2576 
2577 ~~~{.cpp}
2578  mutable struct ns__tuple
2579  {
2580  @ std::string id;
2581  };
2582 
2583  mutable struct ns__tuple
2584  {
2585  std::string name;
2586  std::string value;
2587  };
2588 ~~~
2589 
2590 The members are collected into one definition generated by soapcpp2. Members
2591 may be repeated from one definition to another, but only if their associated
2592 types are identical. So, for example, a third extension with a `value` member
2593 with a different type fails:
2594 
2595 ~~~{.cpp}
2596  mutable struct ns__tuple
2597  {
2598  float value; // BAD: value is already declared std::string
2599  };
2600 ~~~
2601 
2602 The `mutable` concept has proven to be very useful when declaring and
2603 collecting SOAP Headers for multiple services, which are collected into one
2604 `struct SOAP_ENV__Header` by the soapcpp2 tool.
2605 
2606 🔝 [Back to table of contents](#)
2607 
2608 ### Default and fixed member values {#toxsd9-4}
2609 
2610 Class and struct data members in C and C++ may be declared with an optional
2611 default initialization value that is provided "inline" with the declaration of
2612 the member:
2613 
2614 ~~~{.cpp}
2615  class ns__record
2616  {
2617  public:
2618  std::string name = "Joe";
2619  ...
2620  };
2621 ~~~
2622 
2623 Alternatively, you can use C++11 default initialization syntax:
2624 
2625 ~~~{.cpp}
2626  class ns__record
2627  {
2628  public:
2629  std::string name { "Joe" };
2630  ...
2631  };
2632 ~~~
2633 
2634 Any member with a primitive type can be initialized in this way.
2635 
2636 These initializations are performed by the default constructor that is added by
2637 soapcpp2 to each class and struct (in C++ only). A constructor is only added
2638 when a default constructor is not already defined with the class declaration.
2639 
2640 You can explicitly (re)initialize an object with these initial values by using
2641 the soapcpp2 auto-generated functions:
2642 
2643 - `void T::soap_default(struct soap*)` for `class T` (C++ only)
2644 
2645 - `void soap_default_T(struct soap*, T*)` for `struct T` (C and C++).
2646 
2647 If `T` is a struct or class that has a `soap` pointer member to a `::soap`
2648 context then this pointer member will be set to the first argument passed to
2649 these functions to initialize their `soap` pointer member.
2650 
2651 Default value initializations can be provided for members that have primitive
2652 types (`bool`, `enum`, `time_t`, numeric and string types).
2653 
2654 Default value initializations of pointer members is permitted, but the effect
2655 is different. To conform to XML schema validation, an attribute member that is
2656 a pointer to a primitive type will be assigned the default value when parsed
2657 from XML. An element member that is a pointer to a primitive type will be
2658 assigned when the element is empty when parsed from XML.
2659 
2660 As of gSOAP 2.8.48 and greater, a fixed value can be assigned with a `==`. A
2661 fixed value is also verified by the parser's validator.
2662 
2663 Default and fixed values for members with or without pointers are best
2664 explained with the following two example fragments.
2665 
2666 A record class with default values for `std::string` (or `std::wstring`)
2667 attributes and elements is declared as follows:
2668 
2669 ~~~{.cpp}
2670  class ns__record_with_default
2671  {
2672  public:
2673  @ std::string a = "A"; // optional XML attribute with default value "A"
2674  @ std::string b 1 = "B"; // required XML attribute with default value "B"
2675  @ std::string *c = "C"; // optional XML attribute with default value "C"
2676  std::string d 0 = "D"; // optional XML element with default value "D"
2677  std::string e = "E"; // required XML element with default value "E"
2678  std::string *f = "F"; // optional XML element with default value "F"
2679  ...
2680  };
2681 ~~~
2682 
2683 Also `std::unique_ptr` and `std::shared_ptr` may be used instead of a regular
2684 pointer to strings.
2685 
2686 With C `char*` (or `const char*`, `const wchar_t*`) strings in a struct, this
2687 becomes:
2688 
2689 ~~~{.cpp}
2690  struct ns__record_with_default
2691  {
2692  @ char* a = "A"; // optional XML attribute with default value "A"
2693  @ char* b 1 = "B"; // required XML attribute with default value "B"
2694  char* e 1 = "E"; // required XML element with default value "E"
2695  char* f = "F"; // optional XML element with default value "F"
2696  ...
2697  };
2698 ~~~
2699 
2700 By contrast to `std::string e`, `char* e` must be marked `1` to make it
2701 required, because pointer members are optional by default.
2702 
2703 Attributes are considered optional by default, unless marked as required with
2704 the occurrence constraint `1`. Elements are considered required unless the
2705 member type is a pointer or if the member is marked optional with occurrence
2706 constraint `0`.
2707 
2708 Instead of default values, fixed values indicate that the attribute or element
2709 must contain that value, and only that value, when provided in XML. A fixed
2710 value is specified with a `==`.
2711 
2712 Attributes with default or fixed values may be omitted in XML. When absent,
2713 the default/fixed value is used at the receiving side, i.e. the deserializer
2714 assigns the default/fixed value when the attribute is absent. Therefore, there
2715 is no need to make attributes with default/fixed values pointer based, because
2716 there is no way to distinguish an omitted attribute from a populated attribute
2717 on the receiving side. The `c` member in the example above can be a
2718 non-pointer for this reason. The wsdl2h tool does not generate pointers for
2719 attributes with default/fixed values.
2720 
2721 Elements with default or fixed values may be optional and the use of
2722 default/fixed values with elements differs from attributes. The default/fixed
2723 value of an element is only used for elements that are empty in the XML payload
2724 received. Omitted optional elements in the XML payload received are simply
2725 absent; no default/fixed value is assigned.
2726 
2727 @note gSOAP 2.8.106 and greater treat `char*` and `wchar_t*` with explicit
2728 default and fixed values differently than previous versions. Versions prior to
2729 2.8.106 assign the default value when the corresponding XML element is absent,
2730 whereas 2.8.106 and greater assign NULL when the XML element is absent, exactly
2731 as documented in this updated version of this document. To revert to the old
2732 behavior, use <b>`soapcpp2 -z4`</b> option <b>`-z4`</b>. The change affects
2733 members `char* f` and `char* l` (see below).
2734 
2735 A record class (can be a struct in C) with fixed values for attributes and
2736 elements is declared as follows:
2737 
2738 ~~~{.cpp}
2739  class ns__record_with_fixed
2740  {
2741  public:
2742  @ std::string g == "G"; // optional XML attribute with fixed value "G"
2743  @ std::string h 1 == "H"; // required XML attribute with fixed value "H"
2744  @ std::string *i == "I"; // optional XML attribute with fixed value "I"
2745  std::string j 0 == "J"; // optional XML element with fixed value "J"
2746  std::string k == "K"; // required XML element with fixed value "K"
2747  std::string *l == "L"; // optional XML element with fixed value "L"
2748  ...
2749  };
2750 ~~~
2751 
2752 With C `char*` (or `const char*`, `const wchar_t*`) strings in a struct, this
2753 becomes:
2754 
2755 ~~~{.cpp}
2756  struct ns__record_with_fixed
2757  {
2758  @ char* g == "G"; // optional XML attribute with fixed value "G"
2759  @ char* h 1 == "H"; // required XML attribute with fixed value "H"
2760  char* k 1 == "K"; // required XML element with fixed value "K"
2761  char* l == "L"; // optional XML element with fixed value "L"
2762  ...
2763  };
2764 ~~~
2765 
2766 The XML schema validation rules for the examples above are as follows:
2767 
2768 Member | Notes
2769 ------ | ---------------------------------------------------------------------
2770 `a` | attribute may appear once; if it does not appear its value is "A", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "A")
2771 `b` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "B")
2772 `c` | attribute may appear once; if it does not appear its value is "C", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2773 `d` | element may appear once; if it does not appear or if it is empty, its value is "D"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "D")
2774 `e` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "E")
2775 `f` | element may appear once; if it does not appear it is not provided; if it does appear and it is empty, its value is "F"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2776 `g` | attribute may appear once; if it does not appear its value is "G", if it does not appear its value is "G" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "G")
2777 `h` | attribute must appear once, its value must be "H" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "H")
2778 `i` | attribute may appear once; if it does not appear its value is "I", if it does not appear its value is "I" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2779 `j` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "J")
2780 `k` | element must appear once, its value must be "K" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "K")
2781 `l` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2782 
2783 Members of type `char[N]` (fixed length string) can have default and fixed
2784 values, when <b>`soapcpp2 -b`</b> option <b>`-b`</b> is used. Also `char**`
2785 (pointer to a string) members can have default and fixed values. However,
2786 members of this type will be initialized to NULL. The default/fixed values
2787 will be assigned with the same rules as for `char*` when deserialized from XML.
2788 
2789 @see Section [operations on classes and structs](#toxsd9-14).
2790 
2791 🔝 [Back to table of contents](#)
2792 
2793 ### Attribute members {#toxsd9-5}
2794 
2795 Class and struct data members are declared as XML attributes by annotating
2796 their type with a `@` qualifier:
2797 
2798 ~~~{.cpp}
2799  class ns__record
2800  {
2801  public:
2802  @ std::string name; // required (non-pointer means required)
2803  @ uint64_t SSN; // required (non-pointer means required)
2804  ns__record *spouse; // optional (pointer means minOccurs=0)
2805  };
2806 ~~~
2807 
2808 This class maps to a complexType in the soapcpp2-generated XML schema:
2809 
2810 <div class="alt">
2811 ~~~{.xml}
2812  <complexType name="record">
2813  <sequence>
2814  <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
2815  </sequence>
2816  <attribute name="name" type="xsd:string" use="required"/>
2817  <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2818  </complexType>
2819 ~~~
2820 </div>
2821 
2822 An example XML instance of `ns__record` is:
2823 
2824 <div class="alt">
2825 ~~~{.xml}
2826  <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2827  <spouse name="Jane" SSN="1987654320">
2828  </spouse>
2829  </ns:record>
2830 ~~~
2831 </div>
2832 
2833 Attribute data members are restricted to primitive types (`bool`, `enum`,
2834 `time_t`, numeric and string types), `xsd__hexBinary`, `xsd__base64Binary`, and
2835 custom serializers, such as `xsd__dateTime`. Custom serializers for types that
2836 may be used as attributes should define `soap_s2T` and `soap_T2s` functions that
2837 convert values of type `T` to strings and back.
2838 
2839 Attribute data members can be pointers and smart pointers to these types, which
2840 permits attributes to be optional.
2841 
2842 🔝 [Back to table of contents](#)
2843 
2844 ### Backtick XML tags {#toxsd9-5-1}
2845 
2846 The XML tag name of a class/struct member is the name of the member with the
2847 usual XML tag translation, see [colon notation](#toxsd2).
2848 
2849 To override the standard translation of identifier names to XML tag names of
2850 attributes and elements, add the XML tag name in backticks (requires gSOAP
2851 2.8.30 or greater):
2852 
2853 ~~~{.cpp}
2854  class ns__record
2855  {
2856  public:
2857  @ std::string name `full-name`;
2858  @ uint64_t SSN `tax-id`;
2859  ns__record *spouse `married-to`;
2860  };
2861 ~~~
2862 
2863 This class maps to a complexType in the soapcpp2-generated XML schema:
2864 
2865 <div class="alt">
2866 ~~~{.xml}
2867  <complexType name="record">
2868  <sequence>
2869  <element name="married-to" type="ns:record" minOccurs="0" maxOccurs="1"/>
2870  </sequence>
2871  <attribute name="full-name" type="xsd:string" use="required"/>
2872  <attribute name="tax-id" type="xsd:unsignedLong" use="required"/>
2873  </complexType>
2874 ~~~
2875 </div>
2876 
2877 An example XML instance of `ns__record` is:
2878 
2879 <div class="alt">
2880 ~~~{.xml}
2881  <ns:record xmlns:ns="urn:types" full-name="Joe" tax-id="1234567890">
2882  <married-to full-name="Jane" tax-id="1987654320">
2883  </married-to>
2884  </ns:record>
2885 ~~~
2886 </div>
2887 
2888 A backtick XML tag name may contain any non-empty sequence of ASCII and UTF-8
2889 characters except white space and the backtick character. A backtick tag can
2890 be combined with member constraints and default member initializers:
2891 
2892 ~~~{.cpp}
2893  @ uint64_t SSN `tax-id` 0:1 = 999;
2894 ~~~
2895 
2896 🔝 [Back to table of contents](#)
2897 
2898 ### Qualified and unqualified members {#toxsd9-6}
2899 
2900 Class, struct, and union data members are mapped to namespace qualified or
2901 unqualified tag names of local elements and attributes. If a data member has
2902 no prefix then the default form of qualification is applied based on the
2903 element/attribute form that is declared with the XML schema of the class, struct,
2904 or union type. If the member name has a namespace prefix by colon notation,
2905 then the prefix overrules the default (un)qualified form. Therefore,
2906 [colon notation](#toxsd2) is an effective mechanism to control qualification of
2907 tag names of individual members of classes, structs, and unions.
2908 
2909 The XML schema elementFormDefault and attributeFormDefault declarations control
2910 the tag name qualification of local elements and attributes, respectively.
2911 
2912 - "unqualified" indicates that local elements/attributes are not qualified with
2913  the namespace prefix.
2914 
2915 - "qualified" indicates that local elements/attributes must be qualified with
2916  the namespace prefix.
2917 
2918 Individual schema declarations of local elements and attributes may overrule
2919 this by using the form declaration in an XML schema and by using colon notation
2920 to add namespace prefixes to class, struct, and union members in the header
2921 file for soapcpp2.
2922 
2923 Consider for example an `ns__record` class in the `ns` namespace in which local
2924 elements are qualified and local attributes are unqualified by default:
2925 
2926 ~~~{.cpp}
2927  //gsoap ns schema namespace: urn:types
2928  //gsoap ns schema elementForm: qualified
2929  //gsoap ns schema attributeForm: unqualified
2930  class ns__record
2931  {
2932  public:
2933  @ std::string name;
2934  @ uint64_t SSN;
2935  ns__record *spouse;
2936  };
2937 ~~~
2938 
2939 This class maps to a complexType in the soapcpp2-generated XML schema with
2940 targetNamespace "urn:types", elementFormDefault qualified and
2941 attributeFormDefault unqualified:
2942 
2943 <div class="alt">
2944 ~~~{.xml}
2945  <schema targetNamespace="urn:types"
2946  ...
2947  elementFormDefault="qualified"
2948  attributeFormDefault="unqualified"
2949  ... >
2950  <complexType name="record">
2951  <sequence>
2952  <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
2953  </sequence>
2954  <attribute name="name" type="xsd:string" use="required"/>
2955  <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2956  </complexType>
2957  </schema>
2958 ~~~
2959 </div>
2960 
2961 An example XML instance of `ns__record` is:
2962 
2963 <div class="alt">
2964 ~~~{.xml}
2965  <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2966  <ns:spouse> name="Jane" SSN="1987654320">
2967  </ns:spouse>
2968  </ns:record>
2969 ~~~
2970 </div>
2971 
2972 Here the root element <i>`<ns:record>`</i> is qualified because it is a root
2973 element of the XML schema with target namespace "urn:types". Its local element
2974 <i>`<ns:spouse>`</i> is namespace qualified because the elementFormDefault of
2975 local elements is qualified. Attributes are unqualified.
2976 
2977 The default namespace (un)qualification of local elements and attributes can be
2978 overruled by adding a prefix to the member name by using colon notation:
2979 
2980 ~~~{.cpp}
2981  //gsoap ns schema namespace: urn:types
2982  //gsoap ns schema elementForm: qualified
2983  //gsoap ns schema attributeForm: unqualified
2984  class ns__record
2985  {
2986  public:
2987  @ std::string ns:name; // 'ns:' qualified
2988  @ uint64_t SSN;
2989  ns__record *:spouse; // ':' unqualified (no prefix)
2990  };
2991 ~~~
2992 
2993 The colon notation for member <i>`ns:name`</i> forces qualification of its attribute
2994 tag in XML. The colon notation for member <i>`:spouse`</i> removes qualification from
2995 its local element tag:
2996 
2997 <div class="alt">
2998 ~~~{.xml}
2999  <schema targetNamespace="urn:types"
3000  ...
3001  elementFormDefault="unqualified"
3002  attributeFormDefault="unqualified"
3003  ... >
3004  <complexType name="record">
3005  <sequence>
3006  <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" form="unqualified"/>
3007  </sequence>
3008  <attribute name="name" type="xsd:string" use="required" form="qualified"/>
3009  <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
3010  </complexType>
3011  </schema>
3012 ~~~
3013 </div>
3014 
3015 XML instances of `ns__record` have unqualified spouse elements and qualified
3016 ns:name attributes:
3017 
3018 <div class="alt">
3019 ~~~{.xml}
3020  <ns:record xmlns:ns="urn:types" ns:name="Joe" SSN="1234567890">
3021  <spouse> ns:name="Jane" SSN="1987654320">
3022  </spouse>
3023  </ns:record>
3024 ~~~
3025 </div>
3026 
3027 Members of a class or struct can also be prefixed using the `prefix__name`
3028 convention or using colon notation `prefix:name`. However, this has a
3029 different effect by referring to global (root) elements and attributes, see
3030 [document root element definitions](#toxsd9-7).
3031 
3032 [Backtick XML tags](#toxsd9-5-1) can be used in place of the member name
3033 annotations and will achieve the same effect as described when these tag names
3034 are (un)qualified (requires gSOAP 2.8.30 or greater).
3035 
3036 @note You must declare a target namespace with a `//gsoap ns schema namespace:`
3037 directive to enable the `elementForm` and `attributeForm` directives in order
3038 to generate valid XML schemas with soapcpp2. See [directives](#directives) for
3039 more details.
3040 
3041 🔝 [Back to table of contents](#)
3042 
3043 ### Defining document root elements {#toxsd9-7}
3044 
3045 To define and reference XML document root elements we use type names that start
3046 with an underscore:
3047 
3048 ~~~{.cpp}
3049  class _ns__record
3050 ~~~
3051 
3052 Alternatively, we can use a `typedef` to define a document root element with a
3053 given type:
3054 
3055 ~~~{.cpp}
3056  typedef ns__record _ns__record;
3057 ~~~
3058 
3059 This `typedef` maps to a global root element that is added to the
3060 soapcpp2-generated XML schema:
3061 
3062 <div class="alt">
3063 ~~~{.xml}
3064  <element name="record" type="ns:record"/>
3065 ~~~
3066 </div>
3067 
3068 An example XML instance of `_ns__record` is:
3069 
3070 <div class="alt">
3071 ~~~{.xml}
3072  <ns:record xmlns:ns="urn:types">
3073  <name>Joe</name>
3074  <SSN>1234567890</SSN>
3075  <spouse>
3076  <name>Jane</name>
3077  <SSN>1987654320</SSN>
3078  </spouse>
3079  </ns:record>
3080 ~~~
3081 </div>
3082 
3083 Global-level element/attribute definitions are also referenced and/or added to
3084 the generated XML schema when serializable data members reference these by
3085 their qualified name:
3086 
3087 ~~~{.cpp}
3088  typedef std::string _ns__name 1 : 100;
3089  class _ns__record
3090  {
3091  public:
3092  @ _QName xsi__type; // built-in XSD attribute xsi:type
3093  _ns__name ns__name; // ref to global ns:name element
3094  uint64_t SSN;
3095  _ns__record *spouse;
3096  };
3097 ~~~
3098 
3099 These types map to the following comonents in the soapcpp2-generated XML
3100 schema:
3101 
3102 <div class="alt">
3103 ~~~{.xml}
3104  <simpleType name="name">
3105  <restriction base="xsd:string">
3106  <minLength value="1"/>
3107  <maxLength value="100"/>
3108  </restriction>
3109  </simpleType>
3110  <element name="name" type="ns:name"/>
3111  <complexType name="record">
3112  <sequence>
3113  <element ref="ns:name" minOccurs="1" maxOccurs="1"/>
3114  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3115  <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
3116  </sequence>
3117  <attribute ref="xsi:type" use="optional"/>
3118  </complexType>
3119  <element name="record" type="ns:record"/>
3120 ~~~
3121 </div>
3122 
3123 Use only use qualified member names when their types match the global-level
3124 element types that they refer to. For example:
3125 
3126 ~~~{.cpp}
3127  typedef std::string _ns__name; // global element ns:name of type xsd:string
3128  class _ns__record
3129  {
3130  public:
3131  int ns__name; // BAD: global element ns:name is NOT type int
3132  _ns__record ns__record; // OK: ns:record is a global-level root element
3133  ...
3134  };
3135 ~~~
3136 
3137 Therefore, we recommend to use qualified member names only when necessary to
3138 refer to standard XSD elements and attributes, such as `xsi__type`, and
3139 `xsd__lang`.
3140 
3141 By contrast, colon notation has the desired effect to (un)qualify local tag
3142 names by overruling the default element/attribute namespace qualification, see
3143 [qualified and unqualified members](#toxsd9-6).
3144 
3145 As an alternative to prefixing member names, use the backtick tag (requires
3146 gSOAP 2.8.30 or greater):
3147 
3148 ~~~{.cpp}
3149  typedef std::string _ns__name 1 : 100;
3150  class _ns__record
3151  {
3152  public:
3153  @ _QName t <i>`xsi:type`</i>; // built-in XSD attribute xsi:type
3154  _ns__name s <i>`ns:name`</i>; // ref to global ns:name element
3155  uint64_t SSN;
3156  _ns__record *spouse;
3157  };
3158 ~~~
3159 
3160 🔝 [Back to table of contents](#)
3161 
3162 ### (Smart) pointer members and their occurrence constraints {#toxsd9-8}
3163 
3164 A public pointer-typed data member is serialized by following its (smart)
3165 pointer(s) to the value pointed to. To serialize pointers to dynamic arrays of
3166 data, please see the next section on
3167 [container and array members and their occurrence constraints](#toxsd9-9).
3168 
3169 Pointers that are NULL and smart pointers that are empty are serialized to
3170 produce omitted element and attribute values, unless an element is required
3171 and is nillable (struct/class members marked with `nullptr`) in which case the
3172 element is rendered as an empty element with <i>`xsi:nil="true"`</i>.
3173 
3174 To control the occurrence requirements of pointer-based data members,
3175 occurrence constraints are associated with data members in the form of a range
3176 `minOccurs : maxOccurs`. For non-repeatable (meaning, not a container or array)
3177 data members, there are only three reasonable occurrence constraints:
3178 
3179 - `0:0` means that this element or attribute is prohibited.
3180 
3181 - `0:1` means that this element or attribute is optional.
3182 
3183 - `1:1` means that this element or attribute is required.
3184 
3185 Pointer-based data members have a default `0:1` occurrence constraint, making
3186 them optional, and their XML schema local element/attribute definition is
3187 marked as nillable. Non-pointer data members have a default `1:1` occurence
3188 constraint, making them required.
3189 
3190 A `nullptr` occurrence constraint may be applicable to required elements that
3191 are nillable pointer types, thus `nullptr 1:1`. This indicates that the
3192 element is nillable (can be `NULL` or `nullptr`). A pointer data member that
3193 is explicitly marked as required and nillable with `nullptr 1:1` will be
3194 serialized as an element with an <i>`xsi:nil`</i> attribute, thus effectively
3195 revealing the NULL property of its value.
3196 
3197 A non-pointer data member that is explicitly marked as optional with `0:1` will
3198 be set to its default value when no XML value is presented to the deserializer.
3199 A default value can be assigned to a data member that has a primitive type or
3200 is a (smart) pointer to primitive type.
3201 
3202 Consider for example:
3203 
3204 ~~~{.cpp}
3205  class ns__record
3206  {
3207  public:
3208  std::shared_ptr<std::string> name; // optional (pointer means minOccurs=0)
3209  uint64_t SSN 0:1 = 999; // force optional with default 999
3210  ns__record *spouse nullptr 1:1; // force required and nillabe when absent
3211  };
3212 ~~~
3213 
3214 This class maps to a complexType in the soapcpp2-generated XML schema:
3215 
3216 <div class="alt">
3217 ~~~{.xml}
3218  <complexType name="record">
3219  <sequence>
3220  <element name="name" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3221  <element name="SSN" type="xsd:unsignedLong" minOccurs="0" maxOccurs="1" default="999"/>
3222  <element name="spouse" type="ns:record" minOccurs="1" maxOccurs="1" nillable="true"/>
3223  </sequence>
3224  </complexType>
3225 ~~~
3226 </div>
3227 
3228 An example XML instance of `ns__record` with its `name` string value set to
3229 `Joe`, `SSN` set to its default, and `spouse` set to NULL:
3230 
3231 <div class="alt">
3232 ~~~{.xml}
3233  <ns:record xmlns:ns="urn:types" ...>
3234  <name>Joe</name>
3235  <SSN>999</SSN>
3236  <spouse xsi:nil="true"/>
3237  </ns:record>
3238 ~~~
3239 </div>
3240 
3241 @note In general, a smart pointer is simply declared as a `volatile` template
3242 in a interface header file for soapcpp2:
3243 ~~~{.cpp}
3244  volatile template <class T> class NAMESPACE::shared_ptr;
3245 ~~~
3246 
3247 @note The soapcpp2 tool generates code that uses `NAMESPACE::shared_ptr` and
3248 `NAMESPACE::make_shared` to create shared pointers to objects, where
3249 `NAMESPACE` is any valid C++ namespace such as `std` and `boost` if you have
3250 Boost installed.
3251 
3252 🔝 [Back to table of contents](#)
3253 
3254 ### Container and array members and their occurrence constraints {#toxsd9-9}
3255 
3256 Class and struct data member types that are containers `std::deque`,
3257 `std::list`, `std::vector` and `std::set` are serialized as a collection of
3258 the values they contain. You can also serialize dynamic arrays, which is the
3259 alternative for C to store collections of data. Let's start with containers.
3260 
3261 You can use `std::deque`, `std::list`, `std::vector`, and `std::set` containers
3262 by importing:
3263 
3264 ~~~{.cpp}
3265  #import "import/stl.h" // import all containers
3266  #import "import/stldeque.h" // import deque
3267  #import "import/stllist.h" // import list
3268  #import "import/stlvector.h" // import vector
3269  #import "import/stlset.h" // import set
3270 ~~~
3271 
3272 For example, to use a vector data mamber to store names in a record:
3273 
3274 ~~~{.cpp}
3275  #import "import/stlvector.h"
3276  class ns__record
3277  {
3278  public:
3279  std::vector<std::string> names;
3280  uint64_t SSN;
3281  };
3282 ~~~
3283 
3284 To limit the number of names in the vector within reasonable bounds, occurrence
3285 constraints are associated with the container. Occurrence constraints are of
3286 the form `minOccurs : maxOccurs`:
3287 
3288 ~~~{.cpp}
3289  #import "import/stlvector.h"
3290  class ns__record
3291  {
3292  public:
3293  std::vector<std::string> names 1:10;
3294  uint64_t SSN;
3295  };
3296 ~~~
3297 
3298 This class maps to a complexType in the soapcpp2-generated XML schema:
3299 
3300 <div class="alt">
3301 ~~~{.xml}
3302  <complexType name="record">
3303  <sequence>
3304  <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10"/>
3305  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3306  </sequence>
3307  </complexType>
3308 ~~~
3309 </div>
3310 
3311 @note In general, a container is simply declared as a template in an interface
3312 header file for soapcpp2. All class templates are considered containers
3313 (except when declared `volatile`, see smart pointers). For example,
3314 `std::vector` is declared in <i>`gsoap/import/stlvector.h`</i> as:
3315 ~~~{.cpp}
3316  template <class T> class std::vector;
3317 ~~~
3318 
3319 @note You can define and use your own containers. The soapcpp2 tool generates
3320 code that uses the following members of the `template <typename T> class C`
3321 container:
3322 ~~~{.cpp}
3323  void C::clear()
3324  C::iterator C::begin()
3325  C::const_iterator C::begin() const
3326  C::iterator C::end()
3327  C::const_iterator C::end() const
3328  size_t C::size() const
3329  C::iterator C::insert(C::iterator pos, const T& val)
3330 ~~~
3331 
3332 @note For more details see the example `simple_vector` container with
3333 documentation in the package under <i>`gsoap/samples/template`</i>.
3334 
3335 Because C does not support a container template library, we can use a
3336 dynamically-sized array of values. This array is declared as a size-pointer
3337 pair of members within a struct or class. The array size information is stored
3338 in a special size tag member with the name `__size` or `__sizeX`, where `X` can
3339 be any name, or by an `$int` member to identify the member as a special size
3340 tag:
3341 
3342 ~~~{.cpp}
3343  struct ns__record
3344  {
3345  $ int sizeofnames; // array size
3346  char* *names; // array of char* names
3347  uint64_t SSN;
3348  };
3349 ~~~
3350 
3351 This struct maps to a complexType in the soapcpp2-generated XML schema:
3352 
3353 <div class="alt">
3354 ~~~{.xml}
3355  <complexType name="record">
3356  <sequence>
3357  <element name="name" type="xsd:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
3358  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3359  </sequence>
3360  </complexType>
3361 ~~~
3362 </div>
3363 
3364 To limit the number of names in the array within reasonable bounds, occurrence
3365 constraints are associated with the array size member. Occurrence constraints
3366 are of the form `minOccurs : maxOccurs`:
3367 
3368 ~~~{.cpp}
3369  struct ns__record
3370  {
3371  $ int sizeofnames 1:10; // array size 1..10
3372  char* *names; // array of one to ten char* names
3373  uint64_t SSN;
3374  };
3375 ~~~
3376 
3377 This struct maps to a complexType in the soapcpp2-generated XML schema:
3378 
3379 <div class="alt">
3380 ~~~{.xml}
3381  <complexType name="record">
3382  <sequence>
3383  <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10" nillable="true"/>
3384  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3385  </sequence>
3386  </complexType>
3387 ~~~
3388 </div>
3389 
3390 Arrays can also be declared as nested elements, similar to SOAP-encoded dynamic arrays, and these arrays can be used with or without SOAP applications. This requires a separate struct or class with the name of the SOAP array, which should not be qualified with a namespace prefix:
3391 
3392 ~~~{.cpp}
3393  struct ArrayOfstring
3394  {
3395  char* *__ptr 1:100; // array of 1..100 strings
3396  int __size; // array size
3397  };
3398  struct ns__record
3399  {
3400  struct ArrayOfstring names; // array of char* names
3401  uint64_t SSN;
3402  };
3403 ~~~
3404 
3405 The `ns__record` struct maps to a complexType that references the <i>`ArrayOfstring`</i> complexType with an sequence of 1 to 100 <i>`item`</i> elements:
3406 
3407 <div class="alt">
3408 ~~~{.xml}
3409  <complexType name="ArrayOfstring">
3410  <sequence>
3411  <element name="item" type="xsd:string" minOccurs="1" maxOccurs="100"/>
3412  </sequence>
3413  </complexType>
3414  <complexType name="record">
3415  <sequence>
3416  <element name="names" type="ns:ArrayOfstring" minOccurs="1" maxOccurs="1"/>
3417  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3418  </sequence>
3419  </complexType>
3420 ~~~
3421 </div>
3422 
3423 To change the <i>`item`</i> element name in the WSDL, XML schema, and XML messages, use `__ptrName` where `Name` is the name you want to use.
3424 
3425 @note When <b>`soapcpp2 -e`</b> option <b>`-e`</b> is used, the <i>`ArrayOfstring`</i> becomes a SOAP-encoded array for SOAP 1.1/1.2 RPC encoded messaging:
3426 <div class="alt">
3427 ~~~{.xml}
3428  <import namespace="http://schemas.xmlsoap.org/soap/encoding/"/>
3429  <complexType name="ArrayOfstring">
3430  <complexContent>
3431  <restriction base="SOAP-ENC:Array">
3432  <sequence>
3433  <element name="item" type="xsd:string" minOccurs="1" maxOccurs="100"/>
3434  </sequence>
3435  <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="xsd:string[]"/>
3436  </restriction>
3437  </complexContent>
3438  </complexType>
3439  <complexType name="record">
3440  <sequence>
3441  <element name="names" type="ns:ArrayOfstring" minOccurs="1" maxOccurs="1"/>
3442  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3443  </sequence>
3444  </complexType>
3445 ~~~
3446 </div>
3447 
3448 Fixed-size arrays can be used to store a fixed number of values:
3449 
3450 ~~~{.cpp}
3451  struct ns__record
3452  {
3453  char* names[10]; // array of 10 char* names
3454  uint64_t SSN;
3455  };
3456 ~~~
3457 
3458 The fixed-size array is similar to a SOAP-encoded array, which can be used with or without SOAP applications. This struct maps to a complexType that references a <i>`Array10Ofstring`</i> complexType with ten <i>`item`</i> elements:
3459 
3460 <div class="alt">
3461 ~~~{.xml}
3462  <complexType name="record">
3463  <sequence>
3464  <element name="names" type="ns:Array10Ofstring" minOccurs="1" maxOccurs="1"/>
3465  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3466  </sequence>
3467  </complexType>
3468  <complexType name="Array10Ofstring">
3469  <sequence>
3470  <element name="item" type="xsd:string" minOccurs="0" maxOccurs="10"/>
3471  </sequence>
3472  </complexType>
3473 ~~~
3474 </div>
3475 
3476 @note When <b>`soapcpp2 -e`</b> option <b>`-e`</b> is used, the <i>`Array10Ofstring`</i> becomes a SOAP-encoded array for SOAP 1.1/1.2 RPC encoded messaging, see previous note.
3477 
3478 🔝 [Back to table of contents](#)
3479 
3480 ### Sequencing with hidden members {#toxsd9-10}
3481 
3482 A member becomes a hidden XML element, i.e. not visibly rendered in XML, when
3483 its name starts with a double underscore. This makes it possible to sequence a
3484 collection of data members, basically by forming a sequence of elements that
3485 can be optional or repeated together.
3486 
3487 To create a sequence of members that are optional, use a pointer-based hidden
3488 member that is a struct with the collection of members to sequence:
3489 
3490 ~~~{.cpp}
3491  struct ns__record
3492  {
3493  std::string name; // required name
3494  struct __ns__optional
3495  {
3496  uint64_t SSN; // SSN in optional group
3497  std::string phone; // phone number in optional group
3498  } *__optional; // optional group
3499  };
3500 ~~~
3501 
3502 Here we used a hidden struct type `__ns__optional` which starts with a double
3503 underscore, because we do not want to define a new global type for the XML
3504 schema we generate. We just need a unique name for a structure that sequences
3505 the two members.
3506 
3507 This struct maps to a complexType in the soapcpp2-generated XML schema:
3508 
3509 <div class="alt">
3510 ~~~{.xml}
3511  <complexType name="record">
3512  <sequence>
3513  <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3514  <sequence minOccurs="0" maxOccurs="1">
3515  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3516  <element name="phone" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3517  </sequence>
3518  </sequence>
3519  </complexType>
3520 ~~~
3521 </div>
3522 
3523 The `name` member is a required element of the <i>`ns:record`</i> complexType.
3524 The <i>`ns:record`</i> complexType has an optional sequence of `SSN` and
3525 `phone` elements.
3526 
3527 To create repetitions of a sequence of members, use an array as follows:
3528 
3529 ~~~{.cpp}
3530  struct ns__record
3531  {
3532  std::string name; // required name
3533  $ int sizeofarray; // size of group array
3534  struct __ns__array
3535  {
3536  uint64_t SSN; // SSN in group
3537  std::string phone; // phone number in group
3538  } *__array; // group array
3539  };
3540 ~~~
3541 
3542 This struct maps to a complexType in the soapcpp2-generated XML schema:
3543 
3544 <div class="alt">
3545 ~~~{.xml}
3546  <complexType name="record">
3547  <sequence>
3548  <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3549  <sequence minOccurs="0" maxOccurs="unbounded">
3550  <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3551  <element name="phone" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3552  </sequence>
3553  </sequence>
3554  </complexType>
3555 ~~~
3556 </div>
3557 
3558 The `name` member is a required element of the <i>`ns:record`</i> complexType.
3559 The <i>`ns:record`</i> complexType has a potentially unbounded sequence of
3560 `SSN` and `phone` elements. You can specify array bounds instead of zero to
3561 unbounded, see [container and array members and their occurrence constraints](#toxsd9-9).
3562 
3563 The XML value space consists of a sequence of SSN and phone elements:
3564 
3565 <div class="alt">
3566 ~~~{.xml}
3567  <ns:record>
3568  <name>numbers</name>
3569  <SSN>1234567890</SSN>
3570  <phone>555-123-4567</phone>
3571  <SSN>1987654320</SSN>
3572  <phone>555-789-1234</phone>
3573  <SSN>2345678901</SSN>
3574  <phone>555-987-6543</phone>
3575  </ns:record>
3576 ~~~
3577 </div>
3578 
3579 🔝 [Back to table of contents](#)
3580 
3581 ### Tagged union members {#toxsd9-11}
3582 
3583 A union member in a class or in a struct cannot be serialized unless a
3584 discriminating *variant selector* member is provided that tells the serializer
3585 which union field to serialize. This effectively creates a *tagged union*.
3586 
3587 The variant selector is associated with the union as a selector-union pair of members.
3588 The variant selector is a member with the name `__union` or `__unionX`, where
3589 `X` can be any name, or by an `$int` member to identify the member as a variant
3590 selector tag:
3591 
3592 ~~~{.cpp}
3593  class ns__record
3594  {
3595  public:
3596  $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3597  union ns__choice
3598  {
3599  float x;
3600  int n;
3601  char *s;
3602  } u;
3603  std::string name;
3604  };
3605 ~~~
3606 
3607 The variant selector values are auto-generated based on the union name `choice`
3608 and the names of its members `x`, `n`, and `s`:
3609 
3610 - `xORnORs = SOAP_UNION_ns__choice_x` when `u.x` is valid.
3611 
3612 - `xORnORs = SOAP_UNION_ns__choice_n` when `u.n` is valid.
3613 
3614 - `xORnORs = SOAP_UNION_ns__choice_s` when `u.s` is valid.
3615 
3616 - `xORnORs = 0` when none are valid (should only be used with great care,
3617  because XSD validation may fail when content is required but absent).
3618 
3619 This class maps to a complexType with a sequence and choice in the
3620 soapcpp2-generated XML schema:
3621 
3622 <div class="alt">
3623 ~~~{.xml}
3624  <complexType name="record">
3625  <sequence>
3626  <choice>
3627  <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3628  <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3629  <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3630  </choice>
3631  <element name="names" type="xsd:string" minOccurs="1" maxOccurs="1" nillable="true"/>
3632  </sequence>
3633  </complexType>
3634 ~~~
3635 </div>
3636 
3637 A container or dynamic array of a union requires wrapping the variant selector
3638 and union member in a struct:
3639 
3640 ~~~{.cpp}
3641  class ns__record
3642  {
3643  public:
3644  std::vector<
3645  struct ns__data // data with a choice of x, n, or s
3646  {
3647  $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3648  union ns__choice
3649  {
3650  float x;
3651  int n;
3652  char *s;
3653  } u;
3654  }> data; // vector with data
3655  };
3656 ~~~
3657 
3658 and an equivalent definition with a dynamic array instead of a `std::vector`
3659 (you can use this in C with structs):
3660 
3661 ~~~{.cpp}
3662  class ns__record
3663  {
3664  public:
3665  $ int sizeOfdata; // size of dynamic array
3666  struct ns__data // data with a choice of x, n, or s
3667  {
3668  $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3669  union ns__choice
3670  {
3671  float x;
3672  int n;
3673  char *s;
3674  } u;
3675  } *data; // points to the data array of length sizeOfdata
3676  };
3677 ~~~
3678 
3679 This maps to two complexTypes in the soapcpp2-generated XML schema:
3680 
3681 <div class="alt">
3682 ~~~{.xml}
3683  <complexType name="data">
3684  <choice>
3685  <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3686  <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3687  <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3688  </choice>
3689  </complexType>
3690  <complexType name="record">
3691  <sequence>
3692  <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3693  </sequence>
3694  </complexType>
3695 ~~~
3696 </div>
3697 
3698 The XML value space consists of a sequence of item elements each wrapped in an
3699 data element:
3700 
3701 <div class="alt">
3702 ~~~{.xml}
3703  <ns:record xmlns:ns="urn:types" ...>
3704  <data>
3705  <n>123</n>
3706  </data>
3707  <data>
3708  <x>3.1</x>
3709  </data>
3710  <data>
3711  <s>hello</s>
3712  </data>
3713  <data>
3714  <s>world</s>
3715  </data>
3716  </ns:record>
3717 ~~~
3718 </div>
3719 
3720 To remove the wrapping data element, simply rename the wrapping struct to
3721 `__ns__data` and the member to `__data` to make this member invisible to the
3722 serializer. The double underscore prefix naming convention is used for the
3723 struct name and member name. Also use a dynamic array instead of a container
3724 (so you can also use this approach in C with structs):
3725 
3726 ~~~{.cpp}
3727  class ns__record
3728  {
3729  public:
3730  $ int sizeOfdata; // size of dynamic array
3731  struct __ns__data // contains choice of x, n, or s
3732  {
3733  $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3734  union ns__choice
3735  {
3736  float x;
3737  int n;
3738  char *s;
3739  } u;
3740  } *__data; // points to the data array of length sizeOfdata
3741  };
3742 ~~~
3743 
3744 This maps to a complexType in the soapcpp2-generated XML schema:
3745 
3746 <div class="alt">
3747 ~~~{.xml}
3748  <complexType name="record">
3749  <sequence minOccurs="0" maxOccurs="unbounded">
3750  <choice>
3751  <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3752  <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3753  <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3754  </choice>
3755  </sequence>
3756  </complexType>
3757 ~~~
3758 </div>
3759 
3760 The XML value space consists of a sequence of <i>`<x>`</i>, <i>`<n>`</i>, and/or <i>`<s>`</i>
3761 elements:
3762 
3763 <div class="alt">
3764 ~~~{.xml}
3765  <ns:record xmlns:ns="urn:types" ...>
3766  <n>123</n>
3767  <x>3.1</x>
3768  <s>hello</s>
3769  <s>world</s>
3770  </ns:record>
3771 ~~~
3772 </div>
3773 
3774 Please note that structs, classes, and unions are unnested by soapcpp2 (as in
3775 the C standard of nested structs and unions). Therefore, the `ns__choice`
3776 union in the `ns__record` class is redeclared at the top level despite its
3777 nesting within the `ns__record` class. This means that you will have to choose
3778 a unique name for each nested struct, class, and union.
3779 
3780 🔝 [Back to table of contents](#)
3781 
3782 ### Tagged void pointer members {#toxsd9-12}
3783 
3784 To serialize data pointed to by `void*` requires run-time type information that
3785 tells the serializer what type of data to serialize by means of a *tagged void
3786 pointer*. This type information is stored in a special type tag member of a
3787 struct/class with the name `__type` or `__typeX`, where `X` can be any name, or
3788 alternatively by an `$int` special member of any name as a type tag:
3789 
3790 ~~~{.cpp}
3791  class ns__record
3792  {
3793  public:
3794  $ int typeOfdata; // type tag with values SOAP_TYPE_T
3795  void *data; // points to some data of type T
3796  };
3797 ~~~
3798 
3799 A type tag member has nonzero values `SOAP_TYPE_T` where `T` is the name of a
3800 struct/class or the name of a primitive type, such as `int`, `std__string` (for
3801 `std::string`), `string` (for `char*`).
3802 
3803 This class maps to a complexType with a sequence in the soapcpp2-generated
3804 XML schema:
3805 
3806 <div class="alt">
3807 ~~~{.xml}
3808  <complexType name="record">
3809  <sequence>
3810  <element name="data" type="xsd:anyType" minOccurs="0" maxOccurs="1"/>
3811  </sequence>
3812  </complexType>
3813 ~~~
3814 </div>
3815 
3816 The XML value space consists of the XML value space of the type with the
3817 addition of an <i>`xsi:type`</i> attribute to the enveloping element:
3818 
3819 <div class="alt">
3820 ~~~{.xml}
3821  <ns:record xmlns:ns="urn:types" ...>
3822  <data xsi:type="xsd:int">123</data>
3823  </ns:record>
3824 ~~~
3825 </div>
3826 
3827 This <i>`xsi:type`</i> attribute is important for the receiving end to distinguish
3828 the type of data to instantiate. The receiver cannot deserialize the data
3829 without an <i>`xsd:type`</i> attribute.
3830 
3831 You can find the `SOAP_TYPE_T` name of each serializable type in the
3832 auto-generated <i>`soapStub.h`</i> file.
3833 
3834 Also all serializable C++ classes have a virtual `int T::soap_type()` member
3835 that returns their `SOAP_TYPE_T` value that you can use.
3836 
3837 When the `void*` pointer is NULL or when `typeOfdata` is zero, the data is not
3838 serialized.
3839 
3840 A container or dynamic array of `void*` pointers to <i>`xsd:anyType`</i> data
3841 requires wrapping the type tag and `void*` members in a struct:
3842 
3843 ~~~{.cpp}
3844  class ns__record
3845  {
3846  public:
3847  std::vector<
3848  struct ns__data // data with an xsd:anyType item
3849  {
3850  $ int typeOfitem; // type tag with values SOAP_TYPE_T
3851  void *item; // points to some item of type T
3852  }> data; // vector with data
3853  };
3854 ~~~
3855 
3856 and an equivalent definition with a dynamic array instead of a `std::vector`
3857 (you can use this in C with structs):
3858 
3859 ~~~{.cpp}
3860  class ns__record
3861  {
3862  public:
3863  $ int sizeOfdata; // size of dynamic array
3864  struct ns__data // data with an xsd:anyType item
3865  {
3866  $ int typeOfitem; // type tag with values SOAP_TYPE_T
3867  void *item; // points to some item of type T
3868  } *data; // points to the data array of length sizeOfdata
3869  };
3870 ~~~
3871 
3872 This maps to two complexTypes in the soapcpp2-generated XML schema:
3873 
3874 <div class="alt">
3875 ~~~{.xml}
3876  <complexType name="data">
3877  <sequence>
3878  <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1" nillable="true"/>
3879  </sequence>
3880  </complexType>
3881  <complexType name="record">
3882  <sequence>
3883  <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3884  </sequence>
3885  </complexType>
3886 ~~~
3887 </div>
3888 
3889 The XML value space consists of a sequence of item elements each wrapped in a
3890 data element:
3891 
3892 <div class="alt">
3893 ~~~{.xml}
3894  <ns:record xmlns:ns="urn:types" ...>
3895  <data>
3896  <item xsi:type="xsd:int">123</item>
3897  </data>
3898  <data>
3899  <item xsi:type="xsd:double">3.1</item>
3900  </data>
3901  <data>
3902  <item xsi:type="xsd:string">abc</item>
3903  </data>
3904  </ns:record>
3905 ~~~
3906 </div>
3907 
3908 To remove the wrapping data elements, simply rename the wrapping struct and
3909 member to `__data` to make this member invisible to the serializer with the
3910 double underscore prefix naming convention. Also use a dynamic array instead
3911 of a container (you can use this in C with structs):
3912 
3913 ~~~{.cpp}
3914  class ns__record
3915  {
3916  public:
3917  $ int sizeOfdata; // size of dynamic array
3918  struct __data // contains xsd:anyType item
3919  {
3920  $ int typeOfitem; // type tag with values SOAP_TYPE_T
3921  void *item; // points to some item of type T
3922  } *__data; // points to the data array of length sizeOfdata
3923  };
3924 ~~~
3925 
3926 This maps to a complexType in the soapcpp2-generated XML schema:
3927 
3928 <div class="alt">
3929 ~~~{.xml}
3930  <complexType name="record">
3931  <sequence minOccurs="0" maxOccurs="unbounded">
3932  <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1"/>
3933  </sequence>
3934  </complexType>
3935 ~~~
3936 </div>
3937 
3938 The XML value space consists of a sequence of data elements:
3939 
3940 <div class="alt">
3941 ~~~{.xml}
3942  <ns:record xmlns:ns="urn:types" ...>
3943  <item xsi:type="xsd:int">123</item>
3944  <item xsi:type="xsd:double">3.1</item>
3945  <item xsi:type="xsd:string">abc</item>
3946  </ns:record>
3947 ~~~
3948 </div>
3949 
3950 Again, please note that structs, classes, and unions are unnested by soapcpp2
3951 (as in the C standard of nested structs and unions). Therefore, the `__data`
3952 struct in the `ns__record` class is redeclared at the top level despite its
3953 nesting within the `ns__record` class. This means that you will have to choose
3954 a unique name for each nested struct, class, and union.
3955 
3956 @see Section [XSD type bindings](#typemap2).
3957 
3958 🔝 [Back to table of contents](#)
3959 
3960 ### Adding get and set methods {#toxsd9-13}
3961 
3962 A public `get` method may be added to a class or struct, which will be
3963 triggered by the deserializer. This method will be invoked right after the
3964 instance is populated by the deserializer. The `get` method can be used to
3965 update or verify deserialized content. It should return `SOAP_OK` or set
3966 `soap::error` to a nonzero error code and return it.
3967 
3968 A public `set` method may be added to a class or struct, which will be
3969 triggered by the serializer. The method will be invoked just before the
3970 instance is serialized. Likewise, the `set` method should return `SOAP_OK` or
3971 set set `soap::error` to a nonzero error code and return it.
3972 
3973 For example, adding a `set` and `get` method to a class declaration:
3974 
3975 ~~~{.cpp}
3976  class ns__record
3977  {
3978  public:
3979  int set(struct soap*); // triggered before serialization
3980  int get(struct soap*); // triggered after deserialization
3981  ...
3982  };
3983 ~~~
3984 
3985 To add these and othe rmethods to classes and structs with wsdl2h and
3986 <i>`typemap.dat`</i>, please see [class/struct member additions](#typemap3).
3987 
3988 🔝 [Back to table of contents](#)
3989 
3990 ### Operations on classes and structs {#toxsd9-14}
3991 
3992 The following functions/macros are generated by soapcpp2 for each type `T`,
3993 which should make it easier to send, receive, and copy XML data in C and in
3994 C++:
3995 
3996 - `int soap_write_T(struct soap*, T*)` writes an instance of `T` to a file via
3997  file descriptor `int soap::sendfd)` or to a stream via `std::ostream
3998  *soap::os` (C++ only) or saves into a NUL-terminated string by setting
3999  `const char **soap::os` to a string pointer to be set (C only). Returns
4000  `SOAP_OK` on success or an error code, also stored in `soap::error`.
4001 
4002 - `int soap_read_T(struct soap*, T*)` reads an instance of `T` from a file via
4003  file descriptor `int soap::recvfd)` or from a stream via `std::istream
4004  *soap::is` (C++ only) or reads from a NUL-termianted string `const char
4005  *soap::is` (C only). Returns `SOAP_OK` on success or an error code, also
4006  stored in `soap::error`.
4007 
4008 - `void soap_default_T(struct soap*, T*)` sets an instance `T` to its default
4009  value, resetting members of a struct to their initial values (for classes we
4010  use method `T::soap_default`, see below). If `T` is a struct that has a
4011  `soap` pointer member to a `::soap` context then this pointer member will be
4012  set to the first argument passed to this function to initialize its `soap`
4013  pointer member.
4014 
4015 - `T * soap_dup_T(struct soap*, T *dst, const T *src)` (requires <b>`soapcpp2 -Ec`</b>)
4016  deep copy `src` into `dst`, replicating all deep cycles and shared pointers
4017  when a managing `soap` context is provided as argument. When `dst` is NULL,
4018  allocates space for `dst` and returns a pointer to the allocated copy. Deep
4019  copy results in a tree when the `soap` context is NULL, but the presence of
4020  deep cycles will lead to non-termination. Use flag `SOAP_XML_TREE` with
4021  managing context to copy into a tree without cycles and pointers to shared
4022  objects. Returns `dst` or allocated copy when `dst` is NULL.
4023 
4024 - `void soap_del_T(const T*)` (requires <b>`soapcpp2 -Ed`</b>) deletes all
4025  heap-allocated members of this object by deep deletion ONLY IF this object
4026  and all of its (deep) members are not managed by a `soap` context AND the deep
4027  structure is a tree (no cycles and co-referenced objects by way of multiple
4028  (non-smart) pointers pointing to the same data). Can be safely used after
4029  `T * soap_dup_T(NULL, NULL, const T*)` to delete the deep copy returned.
4030  Does not delete the object itself.
4031 
4032 When in C++ mode, soapcpp2 tool adds several methods to classes in addition to
4033 adding a default constructor and destructor (when these were not explicitly
4034 declared).
4035 
4036 The public methods added to a class `T`:
4037 
4038 - `virtual int T::soap_type(void)` returns a unique type ID (`SOAP_TYPE_T`).
4039  This numeric ID can be used to distinguish base from derived instances.
4040 
4041 - `virtual void T::soap_default(struct soap*)` sets all data members to
4042  default values. If class `T` has a `soap` pointer member to a `::soap`
4043  context then this pointer member will be set to the argument passed to this
4044  function to initialize its `soap` pointer member.
4045 
4046 - `virtual void T::soap_serialize(struct soap*) const` serializes object to
4047  prepare for SOAP 1.1/1.2 encoded output (or with `SOAP_XML_GRAPH`) by
4048  analyzing its (cyclic) structures.
4049 
4050 - `virtual int T::soap_put(struct soap*, const char *tag, const char *type) const`
4051  emits object in XML, compliant with SOAP 1.1 encoding style, return error
4052  code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
4053  `soap_end_send(soap)`.
4054 
4055 - `virtual int T::soap_out(struct soap*, const char *tag, int id, const char *type) const`
4056  emits object in XML, with tag and optional id attribute and <i>`xsi:type`</i>,
4057  return error code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
4058  `soap_end_send(soap)`.
4059 
4060 - `virtual void * T::soap_get(struct soap*, const char *tag, const char *type)`
4061  Get object from XML, compliant with SOAP 1.1 encoding style, return pointer
4062  to object or NULL on error. Requires `soap_begin_recv(soap)` and
4063  `soap_end_recv(soap)`.
4064 
4065 - `virtual void *soap_in(struct soap*, const char *tag, const char *type)`
4066  Get object from XML, with matching tag and type (NULL matches any tag and
4067  type), return pointer to object or NULL on error. Requires
4068  `soap_begin_recv(soap)` and `soap_end_recv(soap)`
4069 
4070 - `virtual T * T::soap_alloc(void) const` returns a new object of type `T`,
4071  default initialized and not managed by a `soap` context.
4072 
4073 - `virtual T * T::soap_dup(struct soap*) const` (requires <b>`soapcpp2 -Ec`</b>)
4074  returns a duplicate of this object by deep copying, replicating all deep
4075  cycles and shared pointers when a managing `soap` context is provided as
4076  argument. Deep copy is a tree when argument is NULL, but the presence of
4077  deep cycles will lead to non-termination. Use flag `SOAP_XML_TREE` with the
4078  managing context to copy into a tree without cycles and pointers to shared
4079  objects.
4080 
4081 - `virtual void T::soap_del() const` (rquires <b>`soapcpp2 -Ed`</b>) deletes all
4082  heap-allocated members of this object by deep deletion ONLY IF this object
4083  and all of its (deep) members are not managed by a `soap` context AND the deep
4084  structure is a tree (no cycles and co-referenced objects by way of multiple
4085  (non-smart) pointers pointing to the same data). Can be safely used after
4086  `soap_dup(NULL)` to delete the deep copy. Does not delete the object itself.
4087 
4088 Also, there are four variations of `soap_new_T` for
4089 class/struct/template type `T` that soapcpp2 auto-generates to create instances
4090 on a context-managed heap:
4091 
4092 - `T * soap_new_T(struct soap*)` returns a new instance of `T` with default data
4093  member initializations that are set with the soapcpp2 auto-generated `void
4094  T::soap_default(struct soap*)` method), but ONLY IF the soapcpp2
4095  auto-generated default constructor is used that invokes `soap_default()` and
4096  was not replaced by a user-defined default constructor.
4097 
4098 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
4099  `T`. Similar to the above, instances are initialized.
4100 
4101 - `T * soap_new_req_T(struct soap*, ...)` returns a new instance of `T` and sets
4102  the required data members to the values specified in `...`. The required data
4103  members are those with nonzero minOccurs, see the subsections on
4104  [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
4105  [container and array members and their occurrence constraints](#toxsd9-9).
4106 
4107 - `T * soap_new_set_T(struct soap*, ...)` returns a new instance of `T` and sets
4108  the public/serializable data members to the values specified in `...`.
4109 
4110 The above functions can be invoked with a NULL `soap` context, but we will be
4111 responsible to use `delete T` to remove this instance from the unmanaged heap.
4112 
4113 The allocation functions return NULL when memory allocation failed.
4114 
4115 🔝 [Back to table of contents](#)
4116 
4117 Special classes and structs {#toxsd10}
4118 ---------------------------
4119 
4120 The following applies to both structs and classes. The examples show classes
4121 in C++. For C, use structs and omit the C++ features. Structs also require
4122 the use of the `struct` keyword, otherwise soapcpp2 will throw a syntax error.
4123 
4124 ### SOAP-encoded arrays {#toxsd10-1}
4125 
4126 A class or struct with the following layout is a one-dimensional SOAP-encoded
4127 array type:
4128 
4129 ~~~{.cpp}
4130  class ArrayOfT
4131  {
4132  public:
4133  T *__ptr; // array pointer
4134  int __size; // array size
4135  };
4136 ~~~
4137 
4138 where `T` is the array element type. A multidimensional SOAP Array is:
4139 
4140 ~~~{.cpp}
4141  class ArrayOfT
4142  {
4143  public:
4144  T *__ptr; // array pointer
4145  int __size[N]; // array size of each dimension
4146  };
4147 ~~~
4148 
4149 where `N` is the constant number of dimensions. The pointer points to an array
4150 of `__size[0]*__size[1]* ... * __size[N-1]` elements.
4151 
4152 This maps to a complexType restriction of SOAP-ENC:Array in the
4153 soapcpp2-generated XML schema:
4154 
4155 <div class="alt">
4156 ~~~{.xml}
4157  <complexType name="ArrayOfT">
4158  <complexContent>
4159  <restriction base="SOAP-ENC:Array">
4160  <sequence>
4161  <element name="item" type="T" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
4162  </sequence>
4163  <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="ArrayOfT[]"/>
4164  </restriction>
4165  </complexContent>
4166  </complexType>
4167 ~~~
4168 </div>
4169 
4170 The name of the class can be arbitrary. We often use `ArrayOfT` without a
4171 prefix to distinguish arrays from other classes and structs.
4172 
4173 With SOAP 1.1 encoding, an optional offset member can be added that controls
4174 the start of the index range for each dimension:
4175 
4176 ~~~{.cpp}
4177  class ArrayOfT
4178  {
4179  public:
4180  T *__ptr; // array pointer
4181  int __size[N]; // array size of each dimension
4182  int __offset[N]; // array offsets to start each dimension
4183  };
4184 ~~~
4185 
4186 For example, we can define a matrix of floats as follows:
4187 
4188 ~~~{.cpp}
4189  class Matrix
4190  {
4191  public:
4192  double *__ptr;
4193  int __size[2];
4194  };
4195 ~~~
4196 
4197 The following code populates the matrix and serializes it in XML:
4198 
4199 ~~~{.cpp}
4200  soap *soap = soap_new1(SOAP_XML_INDENT);
4201  Matrix A;
4202  double a[6] = { 1, 2, 3, 4, 5, 6 };
4203  A.__ptr = a;
4204  A.__size[0] = 2;
4205  A.__size[1] = 3;
4206  soap_write_Matrix(soap, &A);
4207 ~~~
4208 
4209 Matrix A is serialized as an array with 2x3 values:
4210 
4211 <div class="alt">
4212 ~~~{.xml}
4213  <SOAP-ENC:Array SOAP-ENC:arrayType="xsd:double[2,3]" ...>
4214  <item>1</item>
4215  <item>2</item>
4216  <item>3</item>
4217  <item>4</item>
4218  <item>5</item>
4219  <item>6</item>
4220  </SOAP-ENC:Array>
4221 ~~~
4222 </div>
4223 
4224 🔝 [Back to table of contents](#)
4225 
4226 ### XSD hexBinary and base64Binary types {#toxsd10-2}
4227 
4228 A special case of a one-dimensional array is used to define <i>`xsd:hexBinary`</i> and
4229 <i>`xsd:base64Binary`</i> types when the pointer type is `unsigned char`:
4230 
4231 ~~~{.cpp}
4232  class xsd__hexBinary
4233  {
4234  public:
4235  unsigned char *__ptr; // points to raw binary data
4236  int __size; // size of data
4237  };
4238 ~~~
4239 
4240 and
4241 
4242 ~~~{.cpp}
4243  class xsd__base64Binary
4244  {
4245  public:
4246  unsigned char *__ptr; // points to raw binary data
4247  int __size; // size of data
4248  };
4249 ~~~
4250 
4251 To create a new binary type, use either one of the following three forms that
4252 declare a new `ns__binary` type that is a <i>`simpleType`</i> restriction of
4253 <i>`xsd:base64Binary`</i>:
4254 
4255 ~~~{.cpp}
4256  typedef xsd__base64Binary ns__binary;
4257 ~~~
4258 ~~~{.cpp}
4259  class ns__binary : public xsd__base64Binary
4260  {
4261  ... // attribute members (@) and class methods
4262  };
4263 ~~~
4264 ~~~{.cpp}
4265  class ns__binary
4266  {
4267  public:
4268  unsigned char *__ptr; // points to raw binary data
4269  int __size; // size of data
4270  ... // attribute members (@) and class methods (optional)
4271  };
4272 ~~~
4273 
4274 Here, `xsd__base64Binary` is reused in the first two cases, where
4275 `xsd__base64Binary` is declared as shown above.
4276 
4277 @see [DIME/MIME/MTOM attachment binary types](#toxsd10-3)
4278 
4279 🔝 [Back to table of contents](#)
4280 
4281 ### DIME/MIME/MTOM attachment binary types {#toxsd10-3}
4282 
4283 A class or struct with a binary content layout can be extended to support
4284 attachments. The following struct or class type can be used as DIME, MIME, and
4285 MTOM attachment and also be used for <i>`xsd:base64Binary`</i> type values:
4286 
4287 ~~~{.cpp}
4288  class xsd__base64Binary
4289  {
4290  public:
4291  unsigned char *__ptr; // points to raw binary data
4292  int __size; // size of data
4293  char *id; // NULL to generate an id, or set to a unique UUID
4294  char *type; // MIME type of the data
4295  char *options; // optional description of MIME attachment
4296  };
4297 ~~~
4298 
4299 When the `id`, `type`, or `options` members are non-NULL, an attachment will be
4300 used instead of base64 XML content. DIME attachments are the default. To
4301 switch to MIME use the `SOAP_ENC_MIME` context flag. To switch to MTOM use the
4302 `SOAP_ENC_MTOM` context flag.
4303 
4304 MTOM is typically used with XOP <i>`<xop:Include>`</i> elements, which is
4305 preferred and declared as follows:
4306 
4307 ~~~{.cpp}
4308  //gsoap xop schema import: http://www.w3.org/2004/08/xop/include
4309  class _xop__Include
4310  {
4311  public:
4312  unsigned char *__ptr; // points to raw binary data
4313  int __size; // size of data
4314  char *id; // NULL to generate an id, or set to a unique UUID
4315  char *type; // MIME type of the data
4316  char *options; // optional description of MIME attachment
4317  };
4318 ~~~
4319 
4320 Attachments are beyond the scope of this article. See the
4321 [gSOAP user guide.](../../guide/html/index.html) for more details.
4322 
4323 🔝 [Back to table of contents](#)
4324 
4325 ### Wrapper class/struct with simpleContent {#toxsd10-4}
4326 
4327 A class or struct with the following layout is a complexType that wraps
4328 simpleContent:
4329 
4330 ~~~{.cpp}
4331  class ns__simple
4332  {
4333  public:
4334  T __item; // primitive type for the simpleContent
4335  ... // attribute members (@) and class methods (optional)
4336  };
4337 ~~~
4338 
4339 The type `T` is a primitive type (`bool`, `enum`, `time_t`, numeric and string
4340 types), `xsd__hexBinary`, `xsd__base64Binary`, and custom serializers, such as
4341 `xsd__dateTime`.
4342 
4343 This maps to a complexType with simpleContent in the soapcpp2-generated XML
4344 schema:
4345 
4346 <div class="alt">
4347 ~~~{.xml}
4348  <complexType name="simple">
4349  <simpleContent>
4350  <extension base="T"/>
4351  </simpleContent>
4352  </complexType>
4353 ~~~
4354 </div>
4355 
4356 A wrapper class/struct may include any number of members that are declared as
4357 attributes with `@`, which should be placed after the `__item` member.
4358 
4359 🔝 [Back to table of contents](#)
4360 
4361 ### DOM anyType and anyAttribute {#toxsd10-5}
4362 
4363 Use of a DOM is optional and enabled by `#import "dom.h"` to use the DOM
4364 `xsd__anyType` element node and `xsd__anyAttribute` attribute node:
4365 
4366 ~~~{.cpp}
4367  #import "dom.h"
4368 
4369  class ns__record
4370  {
4371  public:
4372  @ xsd__anyAttribute attributes; // optional DOM attributes
4373  xsd__anyType *name; // optional DOM element (pointer means minOccurs=0)
4374  xsd__anyType address; // required DOM element (minOccurs=1)
4375  xsd__anyType email 0; // optional DOM element (minOccurs=0)
4376  ... // other members
4377  };
4378 ~~~
4379 
4380 where `name` contains XML stored in a DOM node set and `attributes` is a list
4381 of all visibly rendered attributes. The name `attributes` is arbitrary and any
4382 name will suffice.
4383 
4384 You should place the `xsd__anyType` members at the end of the struct or class.
4385 This ensures that the DOM members are populated last as a "catch all". A
4386 member name starting with double underscore is a wildcard member. These
4387 members are placed at the end of a struct or class automatically by soapcpp2.
4388 
4389 An `#import "dom.h"` import is automatically added by <b>`wsdl2h -d`</b> with
4390 option <b>`-d`</b> to bind <i>`xsd:anyType`</i> to DOM nodes, and also to
4391 populate <i>`xsd:any`</i>, <i>`xsd:anyAttribute`</i> and <i>`xsd:mixed`</i> XML
4392 content:
4393 
4394 ~~~{.cpp}
4395  #import "dom.h"
4396 
4397  class ns__record
4398  {
4399  public:
4400  @ xsd__anyAttribute __anyAttribute; // optional DOM attributes
4401  std::vector<xsd__anyType> __any 0; // optional DOM elements (minOccurs=0)
4402  xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
4403  ... // other members
4404  };
4405 ~~~
4406 
4407 where the members prefixed with `__` are "invisible" to the XML parser, meaning
4408 that these members are not bound to XML tag names.
4409 
4410 In C you can use a dynamic arrary instead of `std::vector`:
4411 
4412 ~~~{.cpp}
4413  #import "dom.h"
4414 
4415  struct ns__record
4416  {
4417  @ xsd__anyAttribute __anyAttribute; // optional DOM attributes
4418  $ int __sizeOfany; // size of the array
4419  xsd__anyType *__any; // optional DOM elements (pointer means minOccurs=0)
4420  xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
4421  ... // other members
4422  };
4423 ~~~
4424 
4425 Classes can inherit DOM, which enables full use of polymorphism with one base
4426 DOM class:
4427 
4428 ~~~{.cpp}
4429  #import "dom.h"
4430 
4431  class ns__record : public xsd__anyType
4432  {
4433  public:
4434  std::vector<xsd__anyType*> array; // array of objects of any class
4435  ... // other members
4436  };
4437 ~~~
4438 
4439 This permits an `xsd__anyType` pointer to refer to a derived class such as
4440 `ns__record`, which will be serialized with an <i>`xsi:type`</i> attribute that is
4441 set to "ns:record". The <i>`xsi:type`</i> attributes add the necessary type information
4442 to distinguish the XML content from the DOM base type. This is important for
4443 the receiving end: without <i>`xsd:type`</i> attributes with type names, only base DOM
4444 objects are recognized and instantiated.
4445 
4446 Because C lacks object-oriented programming concepts such as class inheritance
4447 and polymorphism, you should consider using [derived types in C and C++](#toxsd9-1-1).
4448 
4449 An alternative is to use the special [tagged void pointer members](#toxsd9-12)
4450 to serialize data pointed to by a `void*` member, which can be any serializable
4451 type, such as derived types. This approach uses <i>`xsi:type`</i> attributes
4452 to identify the type of value serialized.
4453 
4454 To ensure that wsdl2h generates pointer-based `xsd__anyType` DOM nodes with
4455 <b>`wsdl2h -d`</b> using option <b>`-d`</b> for <i>`xsd:any`</i>, add the
4456 following line to <i>`typemap.dat`</i>:
4457 
4458  xsd__any = | xsd__anyType*
4459 
4460 This lets wsdl2h produce class/struct members and containers with
4461 `xsd__anyType*` for <i>`xsd:any`</i> instead of `xsd__anyType`. To just force all
4462 <i>`xsd:anyType`</i> uses to be pointer-based, declare in <i>`typemap.dat`</i>:
4463 
4464  xsd__anyType = | xsd__anyType*
4465 
4466 If you use <b>`wsdl2h -d -p`</b> using options <b>`-d`</b> and <b>`-p`</b> then
4467 every class will inherit DOM as shown above. Without option `-d`, an
4468 `xsd__anyType` type is generated to serve as the root type in the type
4469 hierarchy:
4470 
4471 ~~~{.cpp}
4472  class xsd__anyType { _XML __item; struct soap *soap; };
4473 
4474  class ns__record : public xsd__anyType
4475  {
4476  ...
4477  };
4478 ~~~
4479 
4480 where the `_XML __item` member holds any XML content as a literal XML string.
4481 
4482 To use the DOM API, compile <i>`dom.c`</i> (or <i>`dom.cpp`</i> for C++), or
4483 link the gSOAP library with <b>`-lgsoapssl`</b> (or <b>`-lgsoapssl++`</b> for C++).
4484 
4485 @see Documentation of [XML DOM and XPath](http://www.genivia.com/doc/dom/html)
4486 for more details.
4487 
4488 🔝 [Back to table of contents](#)
4489 
4490 Directives {#directives}
4491 ==========
4492 
4493 You can use `//gsoap` directives in the interface header file with the data
4494 binding interface for soapcpp2. These directives are used to configure the
4495 code generated by soapcpp2 by declaring various. properties of Web services
4496 and XML schemas. When using the wsdl2h tool, you will notice that wsdl2h
4497 generates directives automatically based on the WSDL and XSD input.
4498 
4499 Service directives are applicable to service and operations described by WSDL.
4500 Schema directives are applicable to types, elements, and attributes defined by
4501 XML schemas.
4502 
4503 🔝 [Back to table of contents](#)
4504 
4505 Service directives {#directives-1}
4506 ------------------
4507 
4508 A service directive must start at a new line and is of the form:
4509 
4510 ~~~{.cpp}
4511  //gsoap <prefix> service <property>: <value>
4512 ~~~
4513 
4514 where `<prefix>` is the XML namespace prefix of a service binding. The
4515 `<property>` and `<value>` fields are one of the following:
4516 
4517 property | value
4518 --------------- | -----
4519 `name` | name of the service, optionally followed by text describing the service
4520 `namespace` | URI of the WSDL targetNamespace
4521 `documentation` | text describing the service (see also the `name` property), multiple permitted
4522 `doc` | an alias for the `documentation` property
4523 `style` | `document` (default) SOAP messaging style or `rpc` for SOAP RPC
4524 `encoding` | `literal` (default), `encoded` for SOAP encoding, or a custom URI
4525 `protocol` | specifies SOAP or REST, see below
4526 `port` | URL of the service endpoint, usually an http or https address, to use in the WSDL definitions/service/port/address/\@location
4527 `location` | an alias for the `port` property
4528 `endpoint` | an alias for the `port` property
4529 `transport` | URI declaration of the transport, usually `http://schemas.xmlsoap.org/soap/http`
4530 `definitions` | name of the WSDL definitions/\@name
4531 `type` | name of the WSDL definitions/portType/\@name (WSDL2.0 interface/\@name)
4532 `portType` | an alias for the `type` property (`portType` follows SOAP 1.1 naming conventions)
4533 `interface` | an alias for the `type` property (`interface` follows SOAP 1.2 naming conventions)
4534 `binding` | name of the WSDL definitions/binding/\@name
4535 `portName` | name of the WSDL definitions/service/port/\@name
4536 `executable` | name of the "executable" to use in the WSDL definitions/service/port/address/\@location
4537 
4538 The service `name` and `namespace` properties are required in order to generate
4539 a valid WSDL with soapcpp2. The other properties are optional.
4540 
4541 The `style` and `encoding` property defaults are changed with
4542 <b>`soapcpp2 -e`</b> option <b>`-e`</b> to `rpc` and `encoded`, respectively.
4543 
4544 The `protocol` property is `SOAP` by default (SOAP 1.1). Protocol property
4545 values are:
4546 
4547 protocol value | description
4548 -------------- | -----------
4549 `SOAP` | SOAP transport, supporting both SOAP 1.1 and 1.2
4550 `SOAP1.1` | SOAP 1.1 transport (same as `soapcpp2 -1`)
4551 `SOAP1.2` | SOAP 1.2 transport (same as `soapcpp2 -2`)
4552 `SOAP-GET` | one-way SOAP 1.1 or 1.2 with HTTP GET
4553 `SOAP1.1-GET` | one-way SOAP 1.1 with HTTP GET
4554 `SOAP1.2-GET` | one-way SOAP 1.2 with HTTP GET
4555 `HTTP` | non-SOAP REST protocol with HTTP POST
4556 `POST` | non-SOAP REST protocol with HTTP POST
4557 `GET` | non-SOAP REST protocol with HTTP GET
4558 `PUT` | non-SOAP REST protocol with HTTP PUT
4559 `DELETE` | non-SOAP REST protocol with HTTP DELETE
4560 
4561 You can bind service operations to the WSDL namespace of a service by using the
4562 namespace prefix as part of the identifier name of the function that defines
4563 the service operation:
4564 
4565 ~~~{.cpp}
4566  int prefix__func(arg1, arg2, ..., argn, result);
4567 ~~~
4568 
4569 You can override the `port` endpoint URL at runtime in the auto-generated
4570 `soap_call_prefix__func` service call (C/C++ client side) and in the C++ proxy
4571 class service call.
4572 
4573 🔝 [Back to table of contents](#)
4574 
4575 Service method directives {#directives-2}
4576 -------------------------
4577 
4578 Service properties are applicable to a service and to all of its operations.
4579 Service method directives are specifically applicable to a service operation.
4580 
4581 A service method directive is of the form:
4582 
4583 ~~~{.cpp}
4584  //gsoap <prefix> service method-<property>: <method> <value>
4585 ~~~
4586 
4587 where `<prefix>` is the XML namespace prefix of a service binding and
4588 `<method>` is the unqualified name of a service operation. The `<property>`
4589 and `<value>` fields are one of the following:
4590 
4591 method property | value
4592 --------------------------- | -----
4593 `method-documentation` | text describing the service operation
4594 `method` | an alias for the `method-documentation` property
4595 `method-action` | `""` or URI SOAPAction HTTP header, or URL query string for REST protocols
4596 `method-input-action` | `""` or URI SOAPAction HTTP header of service request messages
4597 `method-output-action` | `""` or URI SOAPAction HTTP header of service response messages
4598 `method-fault-action` | `""` or URI SOAPAction HTTP header of service fault messages
4599 `method-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Header
4600 `method-input-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of requests
4601 `method-output-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of responses
4602 `method-fault` | type name of a struct or class member used in `SOAP_ENV__Details` struct
4603 `method-mime-type` | REST content type or SOAP MIME attachment content type(s)
4604 `method-input-mime-type` | REST content type or SOAP MIME attachment content type(s) of request message
4605 `method-output-mime-type` | REST content type or SOAP MIME attachment content type(s) of response message
4606 `method-style` | `document` or `rpc`
4607 `method-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of messages
4608 `method-response-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of response messages
4609 `method-protocol` | SOAP or REST, see [service directives](#directives-1)
4610 
4611 The `method-header-part` properties can be repeated for a service operation to
4612 declare multiple SOAP Header parts that the service operation requires. You
4613 can use `method-input-header-part` and `method-output-header-part` to
4614 differentiate between request and response messages.
4615 
4616 The `method-fault` property can be repeated for a service operation to declare
4617 multiple faults that the service operation may return.
4618 
4619 The `method-action` property serves two purposes:
4620 
4621 -# To set the SOAPAction header for SOAP protocols, i.e. sets the
4622  definitions/binding/operation/SOAP:operation/\@soapAction.
4623 
4624 -# To set the URL query string for endpoints with REST protocols, i.e. sets the
4625  definitions/binding/operation/HTTP:operation/\@location, which specifies
4626  a URL query string (starts with a `?`) to complete the service endpoint URL
4627  or extends the endpoint URL with a local path (starts with a `/`).
4628 
4629 Use `method-input-action` and `method-output-action` to differentiate the
4630 SOAPAction between SOAP request and response messages.
4631 
4632 You can always override the port endpoint URL and action values at runtime in
4633 the auto-generated `soap_call_prefix__func` service call (C/C++ client side)
4634 and in the auto-generated C++ proxy class service calls. A runtime NULL
4635 endpoint URL and/or action uses the defaults set by these directives.
4636 
4637 The `method-mime-type` property serves two purposes:
4638 
4639 -# To set the type of MIME/MTOM attachments used with SOAP protocols. Multiple
4640  attachment types can be declared for a SOAP service operation, i.e. adds
4641  definitions/binding/operation/input/MIME:multipartRelated/MIME:part/MIME:content/\@type
4642  for each type specified.
4643 
4644 -# To set the MIME type of a REST operation. This replaces XML declared in
4645  WSDL by definitions/binding/operation/(input|output)/MIME:mimeXml with
4646  MIME:content/\@type. Use `application/x-www-form-urlencoded` with REST POST
4647  and PUT protocols to send encoded form data automatically instead of XML.
4648  Only primitive type values can be transmitted with form data, such as
4649  numbers and strings, i.e. only types that are legal to use as
4650  [attributes members](#toxsd9-5).
4651 
4652 Use `method-input-mime-type` and `method-output-mime-type` to differentiate the
4653 attachment types between request and response messages.
4654 
4655 🔝 [Back to table of contents](#)
4656 
4657 Schema directives {#directives-3}
4658 -----------------
4659 
4660 A schema directive is of the form:
4661 
4662 ~~~{.cpp}
4663  //gsoap <prefix> schema <property>: <value>
4664 ~~~
4665 
4666 where `<prefix>` is the XML namespace prefix of a schema. The `<property>` and
4667 `<value>` fields are one of the following:
4668 
4669 property | value
4670 --------------- | -----
4671 `namespace` | URI of the XSD targetNamespace
4672 `namespace2` | alternate URI pattern for the XSD namespace (i.e. URI is also accepted by the XML parser)
4673 `import` | URI of an imported namespace, as an alternative or in addition to `namespace`, adds `xsd:import` to the generated WSDL and XSD files
4674 `form` | `unqualified` (default) or `qualified` local element and attribute form defaults
4675 `elementForm` | `unqualified` (default) or `qualified` local element form default
4676 `attributeForm` | `unqualified` (default) or `qualified` local attribute form default
4677 `typed` | `no` (default) or `yes` for serializers to add `xsi:type` attributes to XML
4678 
4679 To learn more about the local form defaults, see [qualified and unqualified members.](#toxsd9-6)
4680 
4681 The `namespace2` URI is a pattern with `*` matching any sequence of characters
4682 and `-` matching any character. This pattern instructs the XML parser and validator
4683 to also accept the URI pattern as a valid namespace for the specified `<prefix>`.
4684 
4685 The `typed` property is implicitly `yes` when <b>`soapcpp2 -t`</b> option <b>`-t`</b> is used.
4686 
4687 🔝 [Back to table of contents](#)
4688 
4689 Schema type directives {#directives-4}
4690 ----------------------
4691 
4692 A schema type directive is of the form:
4693 
4694 ~~~{.cpp}
4695  //gsoap <prefix> schema type-<property>: <name> <value>
4696  //gsoap <prefix> schema type-<property>: <name>::<member> <value>
4697 ~~~
4698 
4699 where `<prefix>` is the XML namespace prefix of a schema and `<name>` is an
4700 unqualified name of a C/C++ type, and the optional `<member>` is a class/struct
4701 members or enum constant.
4702 
4703 You can describe a type with one of the following:
4704 
4705 type property | value
4706 -------------------- | -----
4707 `type-documentation` | text describing the schema type
4708 `type` | an alias for the `type-documentation` property
4709 
4710 For example, you can add a description to an enumeration:
4711 
4712 ~~~{.cpp}
4713  //gsoap ns schema type: Vowels The letters A, E, I, O, U, and sometimes Y
4714  //gsoap ns schema type: Vowels::Y A vowel, sometimes
4715  enum class ns__Vowels : char { A = 'A', E = 'E', I = 'I', O = 'O', U = 'U', Y = 'Y' };
4716 ~~~
4717 
4718 This documented enumeration maps to a simpleType restriction of <i>`xsd:string`</i> in
4719 the soapcpp2-generated schema:
4720 
4721 <div class="alt">
4722 ~~~{.xml}
4723  <simpleType name="Vowels">
4724  <annotation>
4725  <documentation>The letters A, E, I, O, U, and sometimes Y</documentation>
4726  </annotation>
4727  <restriction base="xsd:string">
4728  <enumeration value="A"/>
4729  <enumeration value="E"/>
4730  <enumeration value="I"/>
4731  <enumeration value="O"/>
4732  <enumeration value="U"/>
4733  <enumeration value="Y">
4734  <annotation>
4735  <documentation>A vowel, sometimes</documentation>
4736  </annotation>
4737  <enumeration/>
4738  </restriction>
4739  </simpleType>
4740 ~~~
4741 </div>
4742 
4743 🔝 [Back to table of contents](#)
4744 
4745 Serialization rules {#rules}
4746 ===================
4747 
4748 A presentation on XML data bindings is not complete without discussing the
4749 serialization rules and options that put your data in XML on the wire or store
4750 it a file or buffer.
4751 
4752 There are several options to choose from to serialize data in XML. The choice
4753 depends on the use of the SOAP protocol or if SOAP is not required. The wsdl2h
4754 tool automates this for you by taking the WSDL transport bindings into account
4755 when generating the service functions in C and C++ that use SOAP or REST.
4756 
4757 The gSOAP tools are not limited to SOAP. The tools implement generic XML data
4758 bindings for SOAP, REST, and other uses of XML. So you can read and write XML
4759 using the serializing [operations on classes and structs](#toxsd9-14).
4760 
4761 The following sections briefly explain the serialization rules with respect to
4762 the SOAP protocol for XML Web services. A basic understanding of the SOAP
4763 protocol is useful when developing client and server applications that must
4764 interoperate with other SOAP applications.
4765 
4766 SOAP/REST Web service client and service operations are represented as
4767 functions in your interface header file with the data binding interface for
4768 soapcpp2. The soapcpp2 tool will translate these function to client-side
4769 service invocation calls and server-side service operation dispatchers.
4770 
4771 A discussion of SOAP clients and servers is beyond the scope of this article.
4772 However, the SOAP options discussed here also apply to SOAP client and server
4773 development.
4774 
4775 🔝 [Back to table of contents](#)
4776 
4777 SOAP document versus rpc style {#doc-rpc}
4778 ------------------------------
4779 
4780 The `wsdl:binding/soap:binding/@style` attribute in the <i>`<wsdl:binding>`</i>
4781 section of a WSDL is either "document" or "rpc". The "rpc" style refers to
4782 SOAP RPC (Remote Procedure Call), which is more restrictive than the "document"
4783 style by requiring one XML element in the SOAP Body to act as the procedure
4784 name with XML subelements as its parameters.
4785 
4786 For example, the following directives in the interface header file for soapcpp2
4787 declare that `DBupdate` is a SOAP RPC encoding service method:
4788 
4789 ~~~{.cpp}
4790  //gsoap ns service namespace: urn:DB
4791  //gsoap ns service method-protocol: DBupdate SOAP
4792  //gsoap ns service method-style: DBupdate rpc
4793  int ns__DBupdate(...);
4794 ~~~
4795 
4796 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
4797 one element representing the operation with the parameters as subelements:
4798 
4799 <div class="alt">
4800 ~~~{.xml}
4801  <SOAP-ENV:Envelope
4802  xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4803  xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4804  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4805  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4806  xmlsn:ns="urn:DB">
4807  <SOAP-ENV:Body>
4808  <ns:DBupdate>
4809  ...
4810  </ns:DBupdate>
4811  </SOAP-ENV:Body>
4812  </SOAP-ENV:Envelope>
4813 ~~~
4814 </div>
4815 
4816 The "document" style puts no restrictions on the SOAP Body content. However, we
4817 recommend that the first element's tag name in the SOAP Body should be unique
4818 to each type of operation, so that the receiver can dispatch the operation
4819 based on this element's tag name. Alternatively, the HTTP URL path can be used
4820 to specify the operation, or the HTTP action header can be used to dispatch
4821 operations automatically on the server side (soapcpp2 options -a and -A).
4822 
4823 🔝 [Back to table of contents](#)
4824 
4825 SOAP literal versus encoding {#lit-enc}
4826 ----------------------------
4827 
4828 The `wsdl:operation/soap:body/@use` attribute in the <i>`<wsdl:binding>`</i> section
4829 of a WSDL is either "literal" or "encoded". The "encoded" use refers to the
4830 SOAP encoding rules that support id-ref multi-referenced elements to serialize
4831 data as graphs.
4832 
4833 SOAP encoding is very useful if the data internally forms a graph (including
4834 cycles) and we want the graph to be serialized in XML in a format that ensures
4835 that its structure is preserved. In that case, SOAP 1.2 encoding is the best
4836 option.
4837 
4838 SOAP encoding also adds encoding rules for [SOAP arrays](#toxsd10) to serialize
4839 multi-dimensional arrays. The use of XML attributes to exchange XML data in
4840 SOAP encoding is not permitted. The only attributes permitted are the standard
4841 XSD attributes, SOAP encoding attributes (such as for arrays), and id-ref.
4842 
4843 For example, the following directives in the interface header file for soapcpp2
4844 declare that `DBupdate` is a SOAP RPC encoding service method:
4845 
4846 ~~~{.cpp}
4847  //gsoap ns service namespace: urn:DB
4848  //gsoap ns service method-protocol: DBupdate SOAP
4849  //gsoap ns service method-style: DBupdate rpc
4850  //gsoap ns service method-encoding: DBupdate encoded
4851  int ns__DBupdate(...);
4852 ~~~
4853 
4854 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
4855 an encodingStyle attribute for SOAP 1.1 encoding and an element representing the
4856 operation with parameters that are SOAP 1.1 encoded:
4857 
4858 <div class="alt">
4859 ~~~{.xml}
4860  <SOAP-ENV:Envelope
4861  xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4862  xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4863  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4864  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4865  xmlsn:ns="urn:DB">
4866  <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
4867  <ns:DBupdate>
4868  <records SOAP-ENC:arrayType="ns:record[3]">
4869  <item>
4870  <name href="#_1"/>
4871  <SSN>1234567890</SSN>
4872  </item>
4873  <item>
4874  <name>Jane</name>
4875  <SSN>1987654320</SSN>
4876  </item>
4877  <item>
4878  <name href="#_1"/>
4879  <SSN>2345678901</SSN>
4880  </item>
4881  </records>
4882  </ns:DBupdate>
4883  <id id="_1" xsi:type="xsd:string">Joe</id>
4884  </SOAP-ENV:Body>
4885  </SOAP-ENV:Envelope>
4886 ~~~
4887 </div>
4888 
4889 In the XML fragment shown above the name "Joe" is shared by two records and the
4890 string is referenced by SOAP 1.1 href and id attributes.
4891 
4892 While the soapcpp-generated serializers only introduce multi-referenced
4893 elements in the payload when they are actually multi-referenced in the data
4894 graph, other SOAP applications may render multi-referenced elements more
4895 aggressively. The example could also be rendered as:
4896 
4897 <div class="alt">
4898 ~~~{.xml}
4899  <SOAP-ENV:Envelope
4900  xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4901  xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4902  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4903  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4904  xmlsn:ns="urn:DB">
4905  <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
4906  <ns:DBupdate>
4907  <records SOAP-ENC:arrayType="ns:record[3]">
4908  <item href="#id1"/>
4909  <item href="#id2"/>
4910  <item href="#id3"/>
4911  </records>
4912  </ns:DBupdate>
4913  <id id="id1" xsi:type="ns:record">
4914  <name href="#id4"/>
4915  <SSN>1234567890</SSN>
4916  </id>
4917  <id id="id2" xsi:type="ns:record">
4918  <name href="#id5"/>
4919  <SSN>1987654320</SSN>
4920  </id>
4921  <id id="id3" xsi:type="ns:record">
4922  <name href="#id4"/>
4923  <SSN>2345678901</SSN>
4924  </id>
4925  <id id="id4" xsi:type="xsd:string">Joe</id>
4926  <id id="id5" xsi:type="xsd:string">Jane</id>
4927  </SOAP-ENV:Body>
4928  </SOAP-ENV:Envelope>
4929 ~~~
4930 </div>
4931 
4932 SOAP 1.2 encoding is cleaner and produces more accurate XML encodings of data
4933 graphs by setting the id attribute on the element that is referenced:
4934 
4935 <div class="alt">
4936 ~~~{.xml}
4937  <SOAP-ENV:Envelope
4938  xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope"
4939  xmlns:SOAP-ENC="http://www.w3.org/2003/05/soap-encoding"
4940  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4941  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4942  xmlsn:ns="urn:DB">
4943  <SOAP-ENV:Body>
4944  <ns:DBupdate SOAP-ENV:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
4945  <records SOAP-ENC:itemType="ns:record" SOAP-ENC:arraySize="3">
4946  <item>
4947  <name SOAP-ENC:id="_1">Joe</name>
4948  <SSN>1234567890</SSN>
4949  </item>
4950  <item>
4951  <name>Jane</name>
4952  <SSN>1987654320</SSN>
4953  </item>
4954  <item>
4955  <name SOAP-ENC:ref="_1"/>
4956  <SSN>2345678901</SSN>
4957  </item>
4958  </records>
4959  </ns:DBupdate>
4960  </SOAP-ENV:Body>
4961  </SOAP-ENV:Envelope>
4962 ~~~
4963 </div>
4964 
4965 @note Some SOAP 1.2 applications consider the namespace `SOAP-ENC` of
4966 <i>`SOAP-ENC:id`</i> and <i>`SOAP-ENC:ref`</i> optional. With gSOAP, the SOAP
4967 1.2 encoding serialization follows the 2007 standard, while accepting
4968 unqualified id and ref attributes.
4969 
4970 To remove all rendered id-ref multi-referenced elements, use the
4971 `SOAP_XML_TREE` flag to initialize the `soap` context.
4972 
4973 Some XSD validation rules are turned off with SOAP encoding, because of the
4974 presence of additional attributes, such as id and ref/href, SOAP arrays with
4975 arbitrary element tags for array elements, and the occurrence of additional
4976 multi-ref elements in the SOAP 1.1 Body.
4977 
4978 The use of "literal" puts no restrictions on the XML in the SOAP Body. Full
4979 XSD validation is possible, which can be enabled with the `SOAP_XML_STRICT`
4980 flag to initialize the `soap` context. However, data graphs will be
4981 serialized as trees and cycles in the data will be cut from the XML rendition.
4982 
4983 🔝 [Back to table of contents](#)
4984 
4985 SOAP 1.1 versus SOAP 1.2 {#soap}
4986 ------------------------
4987 
4988 There are two SOAP protocol versions: 1.1 and 1.2. The gSOAP tools can switch
4989 between the two versions seamlessly. You can declare the default SOAP version
4990 for a service operation as follows:
4991 
4992 ~~~{.cpp}
4993  //gsoap ns service method-protocol: DBupdate SOAP1.2
4994 ~~~
4995 
4996 Use `SOAP` (SOAP 1.1), `SOAP1.1`, `SOAP1.2`, and `HTTP` to switch SOAP versions
4997 or enable REST methods with HTTP POST. See [service directives](#directives-1)
4998 and [XML serialization](#non-soap).
4999 
5000 The soapcpp2 tool auto-generates client and server code. At the client side,
5001 this operation sends data with SOAP 1.2 but accepts responses also in SOAP 1.1.
5002 At the server side, this operation accepts requests in SOAP 1.1 and 1.2 and
5003 will return responses in the same SOAP version.
5004 
5005 As we discussed in the previous section, the SOAP 1.2 protocol has a cleaner
5006 multi-referenced element serialization format that greatly enhances the
5007 accuracy of data graph serialization with SOAP RPC encoding and is therefore
5008 recommended.
5009 
5010 The SOAP 1.2 protocol default can also be set by importing and loading
5011 <i>`gsoap/import/soap12.h`</i>:
5012 
5013 ~~~{.cpp}
5014  #import "soap12.h"
5015 ~~~
5016 
5017 Finally, the soapcpp2 tool has options to force SOAP 1.1, SOAP 1.2, or remove
5018 SOAP altogether with <b>`soapcpp2 -1`</b> (SOAP 1.1), <b>`soapcpp2 -2`</b>
5019 (SOAP 1.2) and <b>`soapcpp2 -0`</b> (plain XML, no SOAP).
5020 
5021 🔝 [Back to table of contents](#)
5022 
5023 XML serialization {#non-soap}
5024 -----------------
5025 
5026 You can serialize data to XML that is stored on the heap, on the stack (locals), and
5027 static data as long as the serializable (i.e. non-transient) values are
5028 properly initialized and pointers in the data structures are either NULL or
5029 point to valid structures.
5030 
5031 When XML is deserialized into data, the data is put on the heap and managed by the
5032 `::soap` context, see also [memory management](#memory).
5033 
5034 You can read and write XML directly to a file or stream with the serializing
5035 [operations on classes and structs](#toxsd9-14).
5036 
5037 To define and use XML Web service client and service operations, we can declare
5038 these operations in your interface header file with the data binding interface
5039 for soapcpp2 as functions. The function are translated by soapcpp2 to
5040 client-side service invocation calls and server-side service operation
5041 dispatchers.
5042 
5043 The REST operations POST, GET, and PUT are declared with `//gsoap` directives
5044 in the interface header file for soapcpp2. For example, a REST HTTP POST
5045 operation is declared as follows:
5046 
5047 ~~~{.cpp}
5048  //gsoap ns service namespace: urn:DB
5049  //gsoap ns service method-protocol: DBupdate POST
5050  int ns__DBupdate(...);
5051 ~~~
5052 
5053 There are no SOAP Envelope and SOAP Body elements in the payload for
5054 `DBupdate`. Also the XML serialization rules are identical to SOAP
5055 document/literal, meaning no SOAP RPC encoding XML structures are implicitly
5056 used. The XML payload only has the operation name as an element with its
5057 parameters serialized as subelements:
5058 
5059 <div class="alt">
5060 ~~~{.xml}
5061  <ns:DBupdate xmln:ns="urn:DB" ...>
5062  ...
5063  </ns:DBupdate>
5064 ~~~
5065 </div>
5066 
5067 To force id-ref serialization with REST similar to SOAP 1.2 multi-reference
5068 encoding, use the `SOAP_XML_GRAPH` flag to initialize the `soap` context.
5069 The XML serialization includes id and ref attributes for multi-referenced
5070 elements as follows:
5071 
5072 <div class="alt">
5073 ~~~{.xml}
5074  <ns:DBupdate xmln:ns="urn:DB" ...>
5075  <records>
5076  <item>
5077  <name id="_1">Joe</name>
5078  <SSN>1234567890</SSN>
5079  </item>
5080  <item>
5081  <name>Jane</name>
5082  <SSN>1987654320</SSN>
5083  </item>
5084  <item>
5085  <name ref="_1"/>
5086  <SSN>2345678901</SSN>
5087  </item>
5088  </records>
5089  </ns:DBupdate>
5090 ~~~
5091 </div>
5092 
5093 🔝 [Back to table of contents](#)
5094 
5095 Input and output {#io}
5096 ================
5097 
5098 Reading and writing XML from/to files, streams and string buffers is done via
5099 the managing `soap` context by setting one of the following context variables that
5100 control IO sources and sinks:
5101 
5102 ~~~{.cpp}
5103  soap->recvfd = fd; // an int file descriptor to read from (0 by default)
5104  soap->sendfd = fd; // an int file descriptor to write to (1 by default)
5105  soap->is = &is; // C++ only: a std::istream is object to read from
5106  soap->os = &os; // C++ only: a std::ostream os object to write to
5107  soap->is = cs; // C only: a const char* string to read from (soap->is will advance)
5108  soap->os = &cs; // C only: pointer to a const char*, will be set to point to the string output
5109 ~~~
5110 
5111 Normally, all of these context variables are NULL, which is required to send and
5112 receive data over sockets by gSOAP client and server applications. Therefore,
5113 if you set any of these context variables in a client or server application
5114 then you should reset them to NULL to ensure that socket communications are not
5115 blocked.
5116 
5117 @note The use of `soap::is` and `soap::os` in C requires gSOAP 2.8.28 or greater.
5118 
5119 In the following sections, we present more details on how to read and write to
5120 files and streams, and use string buffers as sources and sinks for XML data.
5121 
5122 In addition, you can set IO callback functions to handle IO at a lower level.
5123 For more details on defining your own callback functions, see the
5124 [gSOAP user guide.](../../guide/html/index.html)
5125 
5126 🔝 [Back to table of contents](#)
5127 
5128 Reading and writing from/to files and streams {#io1}
5129 ---------------------------------------------
5130 
5131 The default IO is standard input and output. Other sources and sinks (those
5132 listed above) will be used until you (re)set them. For example with file-based
5133 input and output:
5134 
5135 ~~~{.cpp}
5136  FILE *fp = fopen("record.xml", "r");
5137  if (fp != NULL)
5138  {
5139  soap->recvfd = fileno(fp); // get file descriptor of file to read from
5140  if (soap_read_ns__record(soap, &pers1))
5141  ... // handle IO error
5142  fclose(fp);
5143  soap->recvfd = 0; // read from stdin, or -1 to block reading
5144  }
5145 
5146  FILE *fp = fopen("record.xml", "w");
5147  if (fp != NULL)
5148  {
5149  soap->sendfd = fileno(fp); // get file descriptor of file to write to
5150  if (soap_write_ns__record(soap, &pers1))
5151  ... // handle IO error
5152  fclose(fp);
5153  soap->sendfd = 1; // write to stdout, or -1 to block writing
5154  }
5155 ~~~
5156 
5157 Similar code with streams in C++:
5158 
5159 ~~~{.cpp}
5160  #include <fstream>
5161 
5162  std::fstream fs;
5163  fs.open("record.xml", std::ios::in);
5164  if (fs)
5165  {
5166  soap->is = &fs;
5167  if (soap_read__ns__record(soap, &pers1))
5168  ... // handle IO error
5169  fs.close();
5170  soap->is = NULL;
5171  }
5172 
5173  fs.open("record.xml", std::ios::out);
5174  if (fs)
5175  {
5176  soap->os = &fs;
5177  if (soap_write__ns__record(soap, &pers1))
5178  ... // handle IO error
5179  fs.close();
5180  soap->os = NULL;
5181  }
5182 ~~~
5183 
5184 🔝 [Back to table of contents](#)
5185 
5186 Reading and writing from/to string buffers {#io2}
5187 ------------------------------------------
5188 
5189 For C++ we recommend to use `std::stringstream` objects from the
5190 <i>`sstream`</i> C++ library as illustrated in the following example:
5191 
5192 ~~~{.cpp}
5193  #include <sstream>
5194 
5195  std::stringstream ss;
5196  ss.str("..."); // XML to parse
5197  soap->is = &ss;
5198  if (soap_read__ns__record(soap, &pers1))
5199  ... // handle IO error
5200  soap->is = NULL;
5201 
5202  soap->os = &ss;
5203  if (soap_write__ns__record(soap, &pers1))
5204  ... // handle IO error
5205  soap->os = NULL;
5206  std::string s = ss.str(); // string with XML
5207 ~~~
5208 
5209 For C we can use `soap::is` and `soap::os` to point to strings of XML content
5210 as follows (this requires gSOAP 2.8.28 or later):
5211 
5212 ~~~{.cpp}
5213  soap->is = "..."; // XML to parse
5214  if (soap_read__ns__record(soap, &pers1))
5215  ... // handle IO error
5216  soap->is = NULL;
5217 
5218  const char *cs = NULL;
5219  soap->os = &cs;
5220  if (soap_write__ns__record(soap, &pers1))
5221  ... // handle IO error
5222  soap->os = NULL;
5223  ... = cs; // string with XML (do not free(cs): managed by the context and freed with soap_end())
5224 ~~~
5225 
5226 The type of `soap::os` is a pointer to a `const char*` string. The pointer is
5227 set by the managing `soap` context to point to the XML data that is stored on
5228 the context-managed heap.
5229 
5230 For earlier gSOAP versions we recommend to use IO callbacks `soap::frecv` and
5231 `soap::fsend`, see the [gSOAP user guide.](../../guide/html/index.html).
5232 
5233 🔝 [Back to table of contents](#)
5234 
5235 Memory management {#memory}
5236 =================
5237 
5238 Memory management with the `soap` context enables us to allocate data in
5239 context-managed heap space that can be collectively deleted. All deserialized
5240 data is placed on the context-managed heap by the `soap` context of the engine.
5241 
5242 🔝 [Back to table of contents](#)
5243 
5244 Memory management in C {#memory1}
5245 ----------------------
5246 
5247 When working with gSOAP in C (i.e. using <b>`wsdl2h -c`</b> option <b>`-c`</b>
5248 or <b>`soapcpp2 -c`</b> option <b>`-c`</b>), data is allocated on the managed heap with:
5249 
5250 - `void *soap_malloc(struct soap*, size_t len)`.
5251 
5252 This function allocates `len` bytes on the heap managed by the specified
5253 context and returns NULL when allocation failed.
5254 
5255 You can also make shallow copies of data with `soap_memdup` that uses
5256 `soap_malloc` and a safe version of `memcpy` to copy a chunk of data `src` with
5257 length `len` to the context-managed heap:
5258 
5259 - `void * soap_memdup(struct soap*, const void *src, size_t len)`
5260 
5261 This function returns a pointer to the copy. This function requires gSOAP
5262 2.8.27 or later.
5263 
5264 In gSOAP 2.8.35 and greater versions, you can use an auto-generated function to
5265 allocate and initialize data of type `T` on the managed heap:
5266 
5267 - `T * soap_new_T(struct soap*, int n)`
5268 
5269 This function returns an array of length `n` of type `T` data that is default
5270 initialized (by internally calling `soap_malloc(soap, n * sizeof(T))` and then
5271 `soap_default_T(soap, T*)` on each array value). Use a negative value or `n=1`
5272 to allocate and initialize a single value. This function returns NULL when
5273 allocation failed.
5274 
5275 The `soap_malloc` function is essentially a wrapper around `malloc`, but
5276 permits the `soap` context to track all heap allocations for collective
5277 deletion with `soap_end(soap)`:
5278 
5279 ~~~{.cpp}
5280  #include "soapH.h"
5281  #include "ns.nsmap"
5282  ...
5283  struct soap *soap = soap_new(); // new context
5284  ...
5285  struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5286  soap_default_ns__record(soap, record); // auto-generated struct initializer
5287  ...
5288  soap_destroy(soap); // only for C++, see section on C++ below
5289  soap_end(soap); // delete record and all other heap allocations
5290  soap_free(soap); // delete context
5291 ~~~
5292 
5293 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
5294 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
5295 the `soap` context and free the context, respectively. Use
5296 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
5297 `soap_done(soap)` only when the context is stack allocated (so cannot be
5298 deleted from the heap).
5299 
5300 The managed heap is checked for memory leaks at run time when the source code
5301 is compiled with option <b>`-DDEBUG`</b>.
5302 
5303 The soapcpp2 auto-generated deserializers in C use `soap_malloc` to allocate
5304 and populate deserialized structures, which are managed by the context for
5305 collective deletion.
5306 
5307 To make `char*` and `wchar_t*` string copies to the context-managed heap, we
5308 can use the functions:
5309 
5310 - `char *soap_strdup(struct soap*, const char *str)` and
5311 
5312 - `wchar_t *soap_wstrdup(struct soap*, const wchar_t *wstr)`.
5313 
5314 If your C compiler supports `typeof` then you can use the following macro to
5315 simplify the managed heap allocation and initialization of primitive values:
5316 
5317 ~~~{.cpp}
5318  #define soap_assign(soap, lhs, rhs) (*(lhs = (typeof(lhs))soap_malloc(soap, sizeof(*lhs))) = rhs)
5319 ~~~
5320 
5321 Pointers to primitive values are often used for optional members. For example,
5322 assume we have the following struct:
5323 
5324 ~~~{.cpp}
5325  struct ns__record
5326  {
5327  const char *name 1; // required (minOccurs=1)
5328  uint64_t *SSN; // optional (pointer means minOccurs=0)
5329  struct ns__record *spouse; // optional (pointer means minOccurs=0)
5330  };
5331 ~~~
5332 
5333 Use `soap_assign` to create a SSN value on the managed heap:
5334 
5335 ~~~{.cpp}
5336  struct soap *soap = soap_new(); // new context
5337  ...
5338  struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5339  soap_default_ns__record(soap, record);
5340  record->name = soap_strdup(soap, "Joe");
5341  soap_assign(soap, record->SSN, 1234567890UL);
5342  ...
5343  soap_end(soap); // delete managed soap_malloc'ed heap data
5344  soap_free(soap); // delete context
5345 ~~~
5346 
5347 Without the `soap_assign` macro, you will need two lines of code, one to
5348 allocate and one to assign (you should also use this if your system can run out
5349 of memory):
5350 
5351 ~~~{.cpp}
5352  assert((record->SSN = (uint64_t*)soap_malloc(soap, sizeof(utint64_t))) != NULL);
5353  *record->SSN = 1234567890UL;
5354 ~~~
5355 
5356 The serializer can serialize any heap, stack, or static allocated data. So we
5357 can also create a new record as follows:
5358 
5359 ~~~{.cpp}
5360  struct soap *soap = soap_new(); // new context
5361  ...
5362  struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5363  static uint64_t SSN = 1234567890UL;
5364  soap_default_ns__record(soap, record);
5365  record->name = "Joe";
5366  record->SSN = &SSN; // safe to use static values: the value of record->SSN is never changed
5367  ...
5368  soap_end(soap); // delete managed soap_malloc'ed heap data
5369  soap_free(soap); // delete context
5370 ~~~
5371 
5372 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
5373 another `soap` context (this requires <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to
5374 generate), here shown for C with the second argument `dst` NULL because we want
5375 to allocate a new managed structure:
5376 
5377 ~~~{.cpp}
5378  struct soap *other_soap = soap_new(); // another context
5379  struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5380  ...
5381  soap_destroy(other_soap); // only for C++, see section on C++ below
5382  soap_end(other_soap); // delete other_record and all of its deep data
5383  soap_free(other_soap); // delete context
5384 ~~~
5385 
5386 The only reason to use another `soap` context and not to use the primary `soap`
5387 context is when the primary context must be destroyed together with all of the
5388 objects it manages while some of the objects must be kept alive. If the
5389 objects that are kept alive contain deep cycles then this is the only option we
5390 have, because deep copy with a managing `soap` context detects and preserves
5391 these cycles unless the `SOAP_XML_TREE` flag is used with the `soap` context:
5392 
5393 ~~~{.cpp}
5394  struct soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
5395  struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5396 ~~~
5397 
5398 The resulting deep copy will be a full copy of the source data structure as a
5399 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
5400 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
5401 
5402 You can also deep copy into unmanaged space and use the auto-generated
5403 `soap_del_T()` function (requires <b>`soapcpp2 -Ed`</b> option <b>`-Ed`</b> to generate) to delete
5404 it later:
5405 
5406 ~~~{.cpp}
5407  struct ns__record *other_record = soap_dup_ns__record(NULL, NULL, record);
5408  ...
5409  soap_del_ns__record(other_record); // deep delete record data members
5410  free(other_record); // delete the record
5411 ~~~
5412 
5413 But you should not do this for any data that has deep cycles in its runtime
5414 data structure. Cycles in the data structure will lead to non-termination when
5415 making unmanaged deep copies. Consider for example:
5416 
5417 ~~~{.cpp}
5418  struct ns__record
5419  {
5420  const char *name 1; // required (minOccurs=1)
5421  uint64_t SSN; // required (non-pointer means minOccurs=1)
5422  struct ns__record *spouse; // optional (pointer means minOccurs=0)
5423  };
5424 ~~~
5425 
5426 The code to populate a structure with a mutual spouse relationship:
5427 
5428 ~~~{.cpp}
5429  struct soap *soap = soap_new();
5430  ...
5431  struct ns__record pers1, pers2;
5432  soap_default_ns__record(soap, &pers1);
5433  soap_default_ns__record(soap, &pers2);
5434  pers1.name = "Joe"; // OK to serialize static data
5435  pers1.SSN = 1234567890;
5436  pers1.spouse = &pers2;
5437  pers2.name = soap_strdup(soap, "Jane"); // allocates and copies a string
5438  pers2.SSN = 1987654320;
5439  pers2.spouse = &pers1;
5440  ...
5441  struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5442  struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5443  soap_set_mode(soap, SOAP_XML_TREE);
5444  struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5445 ~~~
5446 
5447 The bad case is where there is no context used in the first argument. The deep
5448 copy functions use a context to keep track of co-referenced data nodes and
5449 cycles in the data structure copies, to copy co-referenced nodes just once.
5450 Co-references in a data structure are formed by pointers and smart pointers
5451 such as `std::shared_ptr`, such that at least two pointers point to the same
5452 data.
5453 
5454 The serializer can serialize any heap, stack, or static allocated data, such as
5455 in the code shown above. So we can serialize the stack-allocated `pers1`
5456 record as follows:
5457 
5458 ~~~{.cpp}
5459  FILE *fp = fopen("record.xml", "w");
5460  if (fp != NULL)
5461  {
5462  soap->sendfd = fileno(fp); // file descriptor to write to
5463  soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
5464  soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
5465  soap_write_ns__record(soap, &pers1);
5466  fclose(fp);
5467  soap->sendfd = -1; // block further writing
5468  }
5469 ~~~
5470 
5471 which produces an XML document record.xml that is similar to:
5472 
5473 <div class="alt">
5474 ~~~{.xml}
5475  <ns:record xmlns:ns="urn:types" id="Joe">
5476  <name>Joe</name>
5477  <SSN>1234567890</SSN>
5478  <spouse id="Jane">
5479  <name>Jane</name>
5480  <SSN>1987654320</SSN>
5481  <spouse ref="#Joe"/>
5482  </spouse>
5483  </ns:record>
5484 ~~~
5485 </div>
5486 
5487 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
5488 leads to the same non-termination problem when we later try to copy the data
5489 into unmanaged memory heap space:
5490 
5491 ~~~{.cpp}
5492  struct soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
5493  ...
5494  struct ns__record pers1;
5495  FILE *fp = fopen("record.xml", "r");
5496  if (fp != NULL)
5497  {
5498  soap->recvfd = fileno(fp);
5499  if (soap_read_ns__record(soap, &pers1))
5500  ... // handle IO error
5501  fclose(fp);
5502  soap->recvfd = -1; // blocks further reading
5503  }
5504  ...
5505  struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5506  struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5507  soap_set_mode(soap, SOAP_XML_TREE);
5508  struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5509 ~~~
5510 
5511 Copying data with `soap_dup_T(soap)` into managed heap memory space is always
5512 safe. Copying into unmanaged heap memory space requires diligence. But
5513 deleting unmanaged data is easy with `soap_del_T()`.
5514 
5515 You can also use `soap_del_T()` to delete structures that you created in C, but
5516 only if these structures are created with `malloc` and do NOT contain pointers
5517 to stack and static data.
5518 
5519 You can unlink one or more allocated objects from the managed heap to allow the
5520 object to live after `soap_end(soap)` by using:
5521 
5522 - `void soap_unlink(struct soap *soap, void *ptr)`
5523 
5524 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
5525 `soap_end(soap)`. Do not forget to free the data with `free(ptr)`. Be aware
5526 that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If `ptr` is a
5527 struct, pointer members will become invalid when pointing to objects on the
5528 managed heap. Use `soap_unlink(soap, ptr->member)` to unlink `member` as well.
5529 
5530 Finally, when data is allocated in managed memory heap space, either explicitly
5531 with the allocation functions shown above or by the soapcpp2-generated
5532 deserializers, you can delegate the management and deletion of this data to
5533 another `soap` context. That context will be responsible to delete the data
5534 with `soap_end(soap)` later:
5535 
5536 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
5537 
5538 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
5539 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
5540 `soap_from` is stack-allocated) while the managed data remains intact. You
5541 can use this function any time, to delegate management and deletion to another
5542 context `soap_to` and then continue with the current context. You can also use
5543 different source `soap_from` contexts to delegate management and deletion to
5544 the other `soap_to` context. To mass delete all managed data, use
5545 `soap_end(soap_to)`.
5546 
5547 🔝 [Back to table of contents](#)
5548 
5549 Memory management in C++ {#memory2}
5550 ------------------------
5551 
5552 When working with gSOAP in C++, the engine allocates data on a managed heap
5553 using `soap_new_T(soap)` to allocate a type with type name `T`. Managed heap
5554 allocation is tracked by the `soap` context for collective deletion with
5555 `soap_destroy(soap)` for structs, classes, and templates and with
5556 `soap_end(soap)` for everything else.
5557 
5558 You should only use `soap_malloc(struct soap*, size_t len)` to allocate
5559 primitive types because constructors are not invoked. Therefore, `soap_new_T`
5560 is preferred. The auto-generated `T * soap_new_T(struct soap*)` returns data
5561 allocated on the managed heap for type `T`. The data is mass-deleted with
5562 `soap_destroy(soap)` followed by `soap_end(soap)`.
5563 
5564 The `soap_new_T` functions return NULL when allocation fails. C++ exceptions
5565 are never raised by the engine and serializers when data is allocated.
5566 
5567 There are four variations of `soap_new_T` functions to allocate data of type
5568 `T` that soapcpp2 auto-generates:
5569 
5570 - `T * soap_new_T(struct soap*)` returns a new instance of `T` that is default
5571  initialized. For classes, initialization is internally performed using the
5572  soapcpp2 auto-generated `void T::soap_default(struct soap*)` method of the
5573  class, but ONLY IF the soapcpp2 auto-generated default constructor is used
5574  that invokes `soap_default()` and was not replaced by a user-defined default
5575  constructor.
5576 
5577 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
5578  `T`. The instances in the array are default initialized as described above.
5579 
5580 - `T * soap_new_req_T(struct soap*, ...)` (structs and classes only) returns a
5581  new instance of `T` and sets the required data members to the values
5582  specified in `...`. The required data members are those with nonzero
5583  minOccurs, see the subsections on
5584  [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
5585  [container and array members and their occurrence constraints](#toxsd9-9).
5586 
5587 - `T * soap_new_set_T(struct soap*, ...)` (structs and classes only) returns a
5588  new instance of `T` and sets the public/serializable data members to the values
5589  specified in `...`.
5590 
5591 The above functions can be invoked with a NULL `soap` context, but you are then
5592 responsible to use `delete T` to remove this instance from the unmanaged heap.
5593 
5594 For example, to allocate a managed `std::string` you can use:
5595 
5596 ~~~{.cpp}
5597  std::string *s = soap_new_std__string(soap);
5598 ~~~
5599 
5600 To throw a `std::bad_alloc` exception when memory allocation fails, we can define the
5601 following class and macro:
5602 
5603 ~~~{.cpp}
5604  class alloc_check {
5605  public:
5606  template<typename T>
5607  T operator=(T ptr)
5608  {
5609  if (ptr == NULL)
5610  throw std::bad_alloc();
5611  return ptr;
5612  }
5613  };
5614 
5615  #define CHECK alloc_check() =
5616 ~~~
5617 
5618 And use `CHECK` as follows to throw an exception when memory allocation fails:
5619 
5620 ~~~{.cpp}
5621  std::string *s = CHECK soap_new_std__string(soap);
5622 ~~~
5623 
5624 To throw a `std::runtime_exception` when memory allocation fails, with file
5625 and line number information where the error occurred, we can define the
5626 following revised version of our exception-throwing macro:
5627 
5628 ~~~{.cpp}
5629  class alloc_failure : public std::runtime_error {
5630  public:
5631  alloc_failure(const char *file, size_t line) : std::runtime_error(error(file, line))
5632  { }
5633  private:
5634  std::string error(const char *file, size_t line) const
5635  {
5636  std::stringstream ss;
5637  ss << "Memory allocation failed in " << file << " at line " << line;
5638  return ss.str();
5639  }
5640  };
5641 
5642  class alloc_check_with_info {
5643  public:
5644  alloc_check_with_info(const char *file, size_t line) : file(file), line(line)
5645  { }
5646  template<typename T>
5647  T operator=(T ptr) const
5648  {
5649  if (ptr == NULL)
5650  throw alloc_failure(file, line);
5651  return ptr;
5652  }
5653  const char *file;
5654  size_t line;
5655  };
5656 
5657  #define CHECK alloc_check_with_info(__FILE__, __LINE__) =
5658 ~~~
5659 
5660 And use `CHECK` as follows to throw an exception with the file and line number
5661 of the location where memory allocation failed:
5662 
5663 ~~~{.cpp}
5664  std::string *s = CHECK soap_new_std__string(soap);
5665 ~~~
5666 
5667 Primitive types and arrays of primitive values may be allocated with
5668 `soap_malloc` (actually, `soap_new_T` calls `soap_malloc` for primitive type
5669 `T`). All primitive types (i.e. no classes, structs, class templates,
5670 containers, and smart pointers) are allocated with `soap_malloc` for reasons of
5671 efficiency.
5672 
5673 You can use a C++ template to simplify the managed allocation and initialization
5674 of primitive values as follows (this is for primitive types only):
5675 
5676 ~~~{.cpp}
5677  template<class T>
5678  T * soap_make(struct soap *soap, T val)
5679  {
5680  T *p = (T*)soap_malloc(soap, sizeof(T));
5681  if (p == NULL)
5682  throw std::bad_alloc();
5683  *p = val;
5684  return p;
5685  }
5686 ~~~
5687 
5688 For example, assuming we have the following class:
5689 
5690 ~~~{.cpp}
5691  class ns__record
5692  {
5693  public:
5694  std::string name; // required (non-pointer means minOccurs=1)
5695  uint64_t *SSN; // optional (pointer means minOccurs=0)
5696  ns__record *spouse; // optional (pointer means minOccurs=0)
5697  };
5698 ~~~
5699 
5700 You can instantiate a record by using the auto-generated
5701 `soap_new_set_ns__record` and use `soap_make` to create a SSN value on the
5702 managed heap as follows:
5703 
5704 ~~~{.cpp}
5705  soap *soap = soap_new(); // new context
5706  ...
5707  ns__record *record = soap_new_set_ns__record(
5708  soap,
5709  "Joe",
5710  soap_make<uint64_t>(soap, 1234567890UL),
5711  NULL);
5712  ...
5713  soap_destroy(soap); // delete record and all other managed instances
5714  soap_end(soap); // delete managed soap_malloc'ed heap data
5715  soap_free(soap); // delete context
5716 ~~~
5717 
5718 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
5719 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
5720 the `soap` context and free the context, respectively. Use
5721 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
5722 `soap_done(soap)` only when the context is stack allocated (so cannot be
5723 deleted from the heap).
5724 
5725 The managed heap is checked for memory leaks at run time when the source code
5726 is compiled with option <b>`-DDEBUG`</b>.
5727 
5728 However, the serializer can serialize any heap, stack, or static allocated
5729 data. So we can also create a new record as follows:
5730 
5731 ~~~{.cpp}
5732  uint64_t SSN = 1234567890UL;
5733  ns__record *record = soap_new_set_ns__record(soap, "Joe", &SSN, NULL);
5734 ~~~
5735 
5736 which will be fine to serialize this record as long as the local `SSN`
5737 stack-allocated value remains in scope when invoking the serializer and/or
5738 using `record`. It does not matter if `soap_destroy` and `soap_end` are called
5739 beyond the scope of `SSN`.
5740 
5741 To facilitate class methods to access the managing context, we can add a soap
5742 context pointer to a class/struct:
5743 
5744 ~~~{.cpp}
5745  class ns__record
5746  {
5747  public:
5748  ...
5749  void create_more(); // needs a context to create more internal data
5750  protected:
5751  struct soap *soap; // the context that manages this instance, or NULL
5752  };
5753 ~~~
5754 
5755 The `soap` context pointer member of the class is set when invoking
5756 `soap_new_T` (and similar) with a non-NULL context argument that will be
5757 assigned to the `soap` member of the class.
5758 
5759 You can also use a template when an array of pointers to values is required.
5760 To create an array of pointers to values, define the following template:
5761 
5762 ~~~{.cpp}
5763  template<class T>
5764  T **soap_make_array(struct soap *soap, T* array, int n) throw (std::bad_alloc)
5765  {
5766  T **p = (T**)soap_malloc(soap, n * sizeof(T*));
5767  if (p == NULL)
5768  throw std::bad_alloc();
5769  for (int i = 0; i < n; ++i)
5770  p[i] = &array[i];
5771  return p;
5772  }
5773 ~~~
5774 
5775 The `array` parameter is a pointer to an array of `n` values. The template
5776 returns an array of `n` pointers that point to the values in that array:
5777 
5778 ~~~{.cpp}
5779  // create an array of 100 pointers to 100 records
5780  int n = 100;
5781  ns__record **precords = soap_make_array(soap, soap_new_ns__record(soap, n), n);
5782  for (int i = 0; i < n; ++i)
5783  {
5784  precords[i]->name = "...";
5785  precords[i]->SSN = soap_make<uint64_t>(1234567890UL + i);
5786  }
5787 ~~~
5788 
5789 Note that `soap_new_ns__record(soap, n)` returns a pointer to an array of `n`
5790 records, which is then used to create an array of `n` pointers to these records.
5791 
5792 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
5793 another `soap` context (this requires <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to generate), here shown
5794 for C++ with the second argument `dst` NULL to allocate a new managed object:
5795 
5796 ~~~{.cpp}
5797  soap *other_soap = soap_new(); // another context
5798  ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5799  ...
5800  soap_destroy(other_soap); // delete record and other managed instances
5801  soap_end(other_soap); // delete other data (the SSNs on the heap)
5802  soap_free(other_soap); // delete context
5803 ~~~
5804 
5805 To duplicate base and derived instances when a base class pointer or reference
5806 is provided, use the auto-generated method `T * T::soap_dup(struct soap*)`:
5807 
5808 ~~~{.cpp}
5809  soap *other_soap = soap_new(); // another context
5810  ns__record *other_record = record->soap_dup(other_soap);
5811  ...
5812  soap_destroy(other_soap); // delete record and other managed instances
5813  soap_end(other_soap); // delete other data (the SSNs on the heap)
5814  soap_free(other_soap); // delete context
5815 ~~~
5816 
5817 The only reason to use another context and not to use the primary `soap`
5818 context is when the primary context must be destroyed together with all of the
5819 objects it manages while some of the objects must be kept alive. If the
5820 objects that are kept alive contain deep cycles then this is the only option we
5821 have, because deep copy with a managing `soap` context detects and preserves
5822 these cycles unless the `SOAP_XML_TREE` flag is used with the context:
5823 
5824 ~~~{.cpp}
5825  soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
5826  ns__record *other_record = record->soap_dup(other_soap); // deep tree copy
5827 ~~~
5828 
5829 The resulting deep copy will be a full copy of the source data structure as a
5830 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
5831 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
5832 
5833 You can also deep copy into unmanaged space and use the auto-generated
5834 `soap_del_T()` function or the `T::soap_del()` method (requires
5835 <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to generate) to delete it later,
5836 but we should not do this for any data that has deep cycles in its runtime data
5837 structure graph:
5838 
5839 ~~~{.cpp}
5840  ns__record *other_record = record->soap_dup(NULL);
5841  ...
5842  other_record->soap_del(); // deep delete record data members
5843  delete other_record; // delete the record
5844 ~~~
5845 
5846 Cycles in the data structure will lead to non-termination when making unmanaged
5847 deep copies. Consider for example:
5848 
5849 ~~~{.cpp}
5850  class ns__record
5851  {
5852  public:
5853  const char *name 1; // required (minOccurs=1)
5854  uint64_t SSN; // required (non-pointer means minOccurs=1)
5855  ns__record *spouse; // optional (pointer means minOccurs=1)
5856  };
5857 ~~~
5858 
5859 The code to populate a structure with a mutual spouse relationship:
5860 
5861 ~~~{.cpp}
5862  soap *soap = soap_new();
5863  ...
5864  ns__record pers1, pers2;
5865  pers1.name = "Joe";
5866  pers1.SSN = 1234567890;
5867  pers1.spouse = &pers2;
5868  pers2.name = "Jane";
5869  pers2.SSN = 1987654320;
5870  pers2.spouse = &pers1;
5871  ...
5872  ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5873  ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5874  soap_set_mode(soap, SOAP_XML_TREE);
5875  ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5876 ~~~
5877 
5878 The serializer can serialize any heap, stack, or static allocated data, such as
5879 shown in the code shown above. So we can serialize the stack-allocated `pers1`
5880 record as follows:
5881 
5882 ~~~{.cpp}
5883  FILE *fp = fopen("record.xml", "w");
5884  if (fp != NULL)
5885  {
5886  soap->sendfd = fileno(fp); // file descriptor to write to
5887  soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
5888  soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
5889  if (soap_write_ns__record(soap, &pers1))
5890  ... // handle IO error
5891  fclose(fp);
5892  soap->sendfd = -1; // block further writing
5893  }
5894 ~~~
5895 
5896 which produces an XML document record.xml that is similar to:
5897 
5898 <div class="alt">
5899 ~~~{.xml}
5900  <ns:record xmlns:ns="urn:types" id="Joe">
5901  <name>Joe</name>
5902  <SSN>1234567890</SSN>
5903  <spouse id="Jane">
5904  <name>Jane</name>
5905  <SSN>1987654320</SSN>
5906  <spouse ref="#Joe"/>
5907  </spouse>
5908  </ns:record>
5909 ~~~
5910 </div>
5911 
5912 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
5913 leads to the same non-termination problem when we later try to copy the data
5914 into unmanaged space:
5915 
5916 ~~~{.cpp}
5917  soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
5918  ...
5919  ns__record pers1;
5920  FILE *fp = fopen("record.xml", "r");
5921  if (fp != NULL)
5922  {
5923  soap->recvfd = fileno(fp); // file descriptor to read from
5924  if (soap_read_ns__record(soap, &pers1))
5925  ... // handle IO error
5926  fclose(fp);
5927  soap->recvfd = -1; // block further reading
5928  }
5929  ...
5930  ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5931  ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5932  soap_set_mode(soap, SOAP_XML_TREE);
5933  ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5934 ~~~
5935 
5936 Copying data with `soap_dup_T(soap)` into managed space is always safe. Copying
5937 into unmanaged space requires diligence. But deleting unmanaged data is easy
5938 with `soap_del_T()`.
5939 
5940 You can also use `soap_del_T()` to delete structures in C++, but only if these
5941 structures are created with `new` (and `new []` for arrays when applicable) for
5942 classes, structs, and class templates and with `malloc` for anything else, and
5943 the structures do NOT contain pointers to stack and static data.
5944 
5945 You can unlink one or more allocated objects from the managed heap to allow the
5946 object to live after `soap_destroy(soap)` and `soap_end(soap)` by using:
5947 
5948 - `void soap_unlink(struct soap *soap, void *ptr)`
5949 
5950 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
5951 `soap_destroy(soap)` and `soap_end(soap)`. Do not forget to free the data with
5952 `delete ptr` (C++ class instance only) or with `free(ptr)` (non-class data).
5953 Be aware that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If
5954 `ptr` is a struct or class, pointer members will become invalid when pointing
5955 to objects on the managed heap. Use `soap_unlink(soap, ptr->member)` to unlink
5956 `member` as well.
5957 
5958 Finally, when data is allocated in managed memory heap space, either explicitly
5959 with the allocation functions shown above or by the soapcpp2-generated
5960 deserializers, you can delegate the management and deletion of this data to
5961 another `soap` context. That context will be responsible to delete the data
5962 with `soap_destroy(soap)` and `soap_end(soap)` later:
5963 
5964 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
5965 
5966 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
5967 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
5968 `soap_from` is stack-allocated) while the managed data remains intact. You
5969 can use this function any time, to delegate management and deletion to another
5970 context `soap_to` and then continue with the current context. You can also use
5971 different source `soap_from` contexts to delegate management and deletion to
5972 the other `soap_to` context. To mass delete all managed data, use
5973 `soap_destroy(soap_to)` followed by `soap_end(soap_to)`.
5974 
5975 🔝 [Back to table of contents](#)
5976 
5977 Context flags to initialize the soap struct {#flags}
5978 ===========================================
5979 
5980 There are several `soap` context initialization flags and context mode flags to
5981 control XML serialization at runtime. The flags are set with `soap_new1()` to
5982 allocate and initialize a new context:
5983 
5984 ~~~{.cpp}
5985  struct soap *soap = soap_new1(flag1 | flag2 | ... | flagn);
5986  ...
5987  soap_destroy(soap); // delete objects
5988  soap_end(soap); // delete other data and temp data
5989  soap_free(soap); // free context
5990 ~~~
5991 
5992 and with `soap_init1()` for stack-allocated contexts:
5993 
5994 ~~~{.cpp}
5995  struct soap soap;
5996  soap_init1(&soap, flag1 | flag2 | ... | flagn);
5997  ...
5998  soap_destroy(&soap); // delete objects
5999  soap_end(&soap); // delete other data and temp data
6000  soap_done(&soap); // clear context
6001 ~~~
6002 
6003 where `flag1`, `flag2`, ..., `flagn` is one of:
6004 
6005 - `SOAP_C_UTFSTRING`: enables all `std::string` and `char*` strings to
6006  contain UTF-8 content. This option is recommended.
6007 
6008 - `SOAP_C_NILSTRING`: treat empty strings as if they were NULL pointers, i.e.
6009  omits elements and attributes when empty.
6010 
6011 - `SOAP_XML_STRICT`: strictly validates XML while deserializing. Should not be
6012  used together with SOAP 1.1/1.2 encoding style of messaging. Use
6013  <b>`soapcpp2 -s`</b> option <b>`-s`</b> to hard code `SOAP_XML_STRICT` in the
6014  generated serializers. Not recommended with SOAP 1.1/1.2 encoding style
6015  messaging.
6016 
6017 - `SOAP_XML_INDENT`: produces indented XML.
6018 
6019 - `SOAP_XML_CANONICAL`: c14n canonocalization, removes unused `xmlns` bindings
6020  and adds them to appropriate places by applying c14n normalization rules.
6021  Should not be used together with SOAP 1.1/1.2 encoding style messaging.
6022 
6023 - `SOAP_XML_TREE`: write tree XML without id-ref, while pruning data structure
6024  cycles to prevent nontermination of the serializer for cyclic structures.
6025 
6026 - `SOAP_XML_GRAPH`: write graph (digraph and cyclic graphs with shared pointers
6027  to objects) using id-ref attributes. That is, XML with SOAP multi-ref
6028  encoded id-ref elements. This is a structure-preserving serialization format,
6029  because co-referenced data and also cyclic relations are accurately represented.
6030 
6031 - `SOAP_XML_DEFAULTNS`: uses xmlns default namespace declarations, assuming
6032  that the schema attribute form is "qualified" by default (be warned if it is
6033  not, since attributes in the null namespace will get bound to namespaces!).
6034 
6035 - `SOAP_XML_NIL`: emit empty element with <i>`xsi:nil`</i> for all NULL pointers
6036  serialized.
6037 
6038 - `SOAP_XML_IGNORENS`: the XML parser ignores XML namespaces, i.e. element and
6039  attribute tag names match independent of their namespace.
6040 
6041 - `SOAP_XML_NOTYPE`: removes all <i>`xsi:type`</i> attribuation. This option is usually
6042  not needed unless the receiver rejects all <i>`xsi:type`</i> attributes. This option
6043  may affect the quality of the deserializer, which relies on <i>`xsi:type`</i>
6044  attributes to distinguish base class instances from derived class instances
6045  transported in the XML payloads.
6046 
6047 - `SOAP_IO_CHUNK`: to enable HTTP chunked transfers.
6048 
6049 - `SOAP_IO_STORE`: full buffering of outbound messages.
6050 
6051 - `SOAP_ENC_ZLIB`: compress messages, requires compiling with option <b>`-DWITH_GZIP`</b> and
6052  linking with zlib using option <b>`-lz`</b>.
6053 
6054 - `SOAP_ENC_MIME`: enable MIME attachments, see
6055  [DIME/MIME/MTOM attachment binary types](#toxsd10-3).
6056 
6057 - `SOAP_ENC_MTOM`: enable MTOM attachments, see
6058  [DIME/MIME/MTOM attachment binary types](#toxsd10-3).
6059 
6060 @note C++ Web service proxy and service classes have their own `soap` context, either
6061 as a base class (with <b>`soapcpp2 -i`</b> option <b>`-i`</b>) or as a pointer member `soap` that points to
6062 a context (with <b>`soapcpp2 -j`</b> option <b>`-j`</b>). These contexts are allocated when the proxy or
6063 service is instantiated with context flags that are passed to the constructor.
6064 
6065 🔝 [Back to table of contents](#)
6066 
6067 Context parameter settings {#params}
6068 ==========================
6069 
6070 After allocation and initializtion of a `soap` context, several context
6071 parameters can be set (some parameters may require 2.8.31 or greater):
6072 
6073 - `unsigned int soap::maxlevel` is the maximum XML nesting depth levels that
6074  the parser permits. Default initialized to `SOAP_MAXLEVEL` (10000), which is
6075  a redefinable macro in <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxlevel` to a
6076  lower value to restrict XML parsing nesting depth.
6077 
6078 - `long soap::maxlength` is the maximum string content length if not already
6079  constrained by an XML schema validation `maxLength` constraint. Zero means
6080  unlimited string lengths are permitted (unless restricted by XML schema
6081  `maxLength`). Default initialized to `SOAP_MAXLENGTH` (0), which is a
6082  redefinable macro in <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxlength` to a
6083  positive value to restrict the number of (wide) characters in strings parsed,
6084  restrict hexBinary byte length, and restrict base64Binary byte length.
6085 
6086 - `size_t soap::maxoccurs` is the maximum number of array or container elements
6087  permitted by the parser. Must be greater than zero (0). Default initialized
6088  to `SOAP_MAXOCCURS` (100000), which is a redefinable macro in
6089  <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxoccurs` to a positive value to
6090  restrict the number of array and container elements that can be parsed.
6091 
6092 - `soap::version` is the SOAP version used, with 0 for non-SOAP, 1 for SOAP1.1,
6093  and 2 for SOAP1.2. This value is normally set by web service operations, and
6094  is otherwise 0 (non-SOAP). Use `soap_set_version(struct soap*, short)` to
6095  set the value. This controls XML namespaces and SOAP id-ref serialization
6096  when applicable with an encodingStyle (see below).
6097 
6098 - `const char *soap::encodingStyle` is a string that is used with SOAP
6099  encoding, normally NULL for non-SOAP XML. Set this string to "" (empty
6100  string) to enable SOAP encoding style, which supports id-ref graph
6101  serialization (see also the `SOAP_XML_GRAPH` [context flag](#flags)).
6102 
6103 - `int soap::recvfd` is the file descriptor to read and parse source data from.
6104  Default initialized to 0 (stdin). See also [input and output](#io).
6105 
6106 - `int soap::sendfd` is the file descriptor to write data to. Default
6107  initialized to 1 (stdout). See also [input and output](#io).
6108 
6109 - `const char *is` for C: string to read and parse source data from, overriding
6110  the `recvfd` source. Normally NULL. This value must be reset to NULL or
6111  the parser will continue to read from this string content until the NUL
6112  character. See also [input and output](#io).
6113 
6114 - `std::istream *is` for C++: an input stream to read and parse source data
6115  from, overriding the `recvfd` source. Normally NULL. This value must be
6116  reset to NULL or the parser will continue to read from this stream until EOF.
6117  See also [input and output](#io).
6118 
6119 - `const char **os` for C: points to a string (a `const char *`) that will be
6120  set to point to the string output. Normally NULL. This value must be reset
6121  to NULL or the next output will result in reassigning the pointer to point to
6122  the next string that is output. The strings are automatically deallocated by
6123  `soap_end(soap)`. See also [input and output](#io).
6124 
6125 - `std::ostream *os` for C++: an output stream to write output to. Normally
6126  NULL. This value must be reste to NULL or the next output will be send to
6127  this stream. See also [input and output](#io).
6128 
6129 🔝 [Back to table of contents](#)
6130 
6131 Error handling and reporting {#errors}
6132 ============================
6133 
6134 The gSOAP API functions return `SOAP_OK` (zero) or a non-zero error code. The
6135 error code is stored in `int soap::error` of the current `soap` context.
6136 Error messages can be displayed with:
6137 
6138 - `void soap_stream_fault(struct soap*, std::ostream &os)` for C++ only, prints
6139  the error message to an output stream.
6140 
6141 - `void soap_print_fault(struct soap*, FILE *fd)` prints the error message to a
6142  FILE descriptor.
6143 
6144 - `void soap_sprint_fault(struct soap*, char *buf, size_t len)` saves the error
6145  message to a fixed-size buffer allocated with a maximum length.
6146 
6147 - `void soap_print_fault_location(struct soap*, FILE *fd)` prints the location
6148  and part of the XML where the parser encountered an error.
6149 
6150 C++ exceptions are never raised by the engine or serializers, even when data is
6151 allocated.
6152 
6153 A `SOAP_EOM` error code is returned when memory was exhausted during
6154 processing of input and/or output of data.
6155 
6156 An EOF (`SOAP_EOF` or -1) error code is returned when the parser has hit EOF
6157 but expected more input, or when socket communications timed out. In addition
6158 to the `SOAP_EOF` error, the `int soap::errnum` of the `soap` context is
6159 set to the `errno` value of the operation that failed. For timeouts, the
6160 `soap::ernum` value is always 0 instead of an `errno` error code.
6161 
6162 Use `soap_xml_error_check(soap->error)` to check for XML errors. This returns
6163 true (non-zero) when a parsing and validation error has occurred.
6164 
6165 For example:
6166 
6167 ~~~{.cpp}
6168  #include <sstream>
6169 
6170  struct soap *soap = soap_new1(SOAP_XML_INDENT | SOAP_XML_STRICT | SOAP_XML_TREE);
6171  struct ns__record person;
6172  std::stringstream ss;
6173  ss.str("..."); // XML to parse
6174  soap->is = &ss;
6175  if (soap_read__ns__record(soap, &person))
6176  {
6177  if (soap_xml_error_check(soap->error))
6178  std::cerr << "XML parsing error!" << std::endl;
6179  else
6180  soap_stream_fault(soap, std::cerr);
6181  }
6182  else
6183  {
6184  ... // all OK, use person record
6185  }
6186  soap_destroy(soap); // delete objects
6187  soap_end(soap); // delete other data and temp data
6188  soap_free(soap); // free context
6189 ~~~
6190 
6191 When deploying your application on UNIX and Linux systems, UNIX signal handlers
6192 should be added to your code handle signals, in particular `SIGPIPE`:
6193 
6194 ~~~{.cpp}
6195  signal(SIGPIPE, sigpipe_handler);
6196 ~~~
6197 
6198 where the `sigpipe_handler` is a function:
6199 
6200 ~~~{.cpp}
6201  void sigpipe_handler(int x) { }
6202 ~~~
6203 
6204 Other UNIX signals may have to be handled as well.
6205 
6206 The engine is designed for easy memory cleanup after being interrupted. Use
6207 `soap_destroy(soap)` and `soap_end(soap)`, after which the `soap` context can
6208 be reused.
6209 
6210 🔝 [Back to table of contents](#)
6211 
6212 Features and limitations {#features}
6213 ========================
6214 
6215 In general, to use the generated code:
6216 
6217 - Make sure to `#include "soapH.h"` in your code and also define a namespace
6218  table or `#include "ns.nsmap"` with the generated table, where `ns` is the
6219  namespace prefix for services.
6220 
6221 - Use <b>`soapcpp2 -j`</b> option <b>`-j`</b> (C++ only) to generate C++ proxy and service objects.
6222  The auto-generated files include documented inferfaces. Compile with
6223  <i>`soapC.cpp`</i> and link with <b>`-lgsoap++`</b>, or alternatively compile
6224  <i>`gsoap/stdsoap2.cpp`</i>.
6225 
6226 - Without <b>`soapcpp2 -j`</b> option <b>`-j`</b>: client-side uses the auto-generated
6227  <i>`soapClient.cpp`</i> and <i>`soapC.cpp`</i> (or C versions of those).
6228  Compile and link with <b>`-lgsoap++`</b> (<b>`-lgsoap`</b> for C), or
6229  alternatively compile <i>`gsoap/stdsoap2.cpp`</i> (<i>`gsoap/stdsoap2.c`</i>
6230  for C).
6231 
6232 - Without <b>`soapcpp2 -j`</b> option <b>`-j`</b>: server-side uses the
6233  auto-generated <i>`soapServer.cpp`</i> and <i>`soapC.cpp`</i> (or C versions
6234  of those). Compile and link with <b>`-lgsoap++`</b> (<b>`-lgsoap`</b> for
6235  C), or alternatively compile <i>`gsoap/stdsoap2.cpp`</i> (<i>`stdsoap2.c`</i>
6236  for C).
6237 
6238 - Use `soap_new()` or `soap_new1(int flags)` to allocate and initialize a
6239  heap-allocated `soap` context with or without flags. Delete this `soap` context with
6240  `soap_free(struct soap*)`, but only after `soap_destroy(struct soap*)` and
6241  `soap_end(struct soap*)`.
6242 
6243 - Use `soap_init(struct *soap)` or `soap_init1(struct soap*, int flags)` to
6244  initialize a stack-allocated `soap` context with or without flags. End the use of
6245  this context with `soap_done(struct soap*)`, but only after
6246  `soap_destroy(struct soap*)` and `soap_end(struct soap*)`.
6247 
6248 Additional notes with respect to the wsdl2h and soapcpp2 tools:
6249 
6250 - Nested classes, structs, and unions in a interface header file are unnested
6251  by soapcpp2.
6252 
6253 - Use `#import "file.h"` instead of `#include` to import other header files in
6254  a interface header file for soapcpp2. The `#include`, `#define`, and
6255  `#pragma` are accepted by soapcpp2, but are moved to the very start of the
6256  generated code for the C/C++ compiler to include before all generated
6257  definitions. Often it is useful to add an `#include` with a
6258  [volatile type](#toxsd9-2) that includes the actual type declaration, and to
6259  ensure transient types are declared when these are used in a data binding
6260  interface declared in a interface header file for soapcpp2.
6261 
6262 - To remove any SOAP-specific bindings, use <b>`soapcpp2 -0`</b> option <b>`-0`</b>.
6263 
6264 - A interface header file for soapcpp2 should not include any code statements,
6265  only data type declarations. This includes constructor initialization lists
6266  that are not permitted. Use member initializations instead.
6267 
6268 - C++ namespaces are supported. Use <b>`wsdl2h -qname`</b> option
6269  <b>`-qname`</b> to add C++ namespace `name`. Or add a `namespace name { ... }`
6270  to the header file, but the `{ ... }` must cover the entire
6271  header file content from begin to end.
6272 
6273 - Optional XML DOM support can be used to store mixed content or literal XML
6274  content. Otherwise, mixed content may be lost. Use <b>`wsdl2h -d`</b>
6275  option <b>`-d`</b> for XML DOM support and compile and link with
6276  <i>`gsoap/dom.c`</i> or <i>`gsoap/dom.cpp`</i>. For details,
6277  see [XML DOM and XPath](http://www.genivia.com/doc/dom/html).
6278 
6279 🔝 [Back to table of contents](#)
6280 
6281 Removing SOAP namespaces from XML payloads {#nsmap}
6282 ==========================================
6283 
6284 The soapcpp2 tool generates a <i>`.nsmap`</i> file that includes two bindings for SOAP
6285 namespaces. We can remove all SOAP namespaces (and SOAP processing logic) with
6286 <b>`soapcpp2 -0`</b> option <b>`-0`</b> or by simply setting the two entries to NULL:
6287 
6288 ~~~{.cpp}
6289  struct Namespace namespaces[] =
6290  {
6291  {"SOAP-ENV", NULL, NULL, NULL},
6292  {"SOAP-ENC", NULL, NULL, NULL},
6293  ...
6294  };
6295 ~~~
6296 
6297 Once the <i>`.nsmap`</i> is generated, you can copy-paste the content into your
6298 project code. However, if we rerun wsdl2h on updated WSDL/XSD files or
6299 <i>`typemap.dat`</i> declarations then we need to use the updated table.
6300 
6301 In cases that no XML namespaces are used at all, for example with
6302 [XML-RPC](http://www.genivia.com/doc/xml-rpc-json/html), you may use an empty
6303 namespace table:
6304 
6305 ~~~{.cpp}
6306  struct Namespace namespaces[] = {{NULL,NULL,NULL,NULL}};
6307 ~~~
6308 
6309 However, beware that any built-in xsi attributes that are rendered will lack
6310 the proper namespace binding. At least we suggest to use `SOAP_XML_NOTYPE` for
6311 this reason.
6312 
6313 🔝 [Back to table of contents](#)
6314 
6315 Examples {#examples}
6316 ========
6317 
6318 Select the project files below to peruse the source code examples.
6319 
6320 🔝 [Back to table of contents](#)
6321 
6322 Source files
6323 ------------
6324 
6325 - <i>`address.xsd`</i> Address book schema
6326 - <i>`address.cpp`</i> Address book app (reads/writes address.xml file)
6327 - <i>`addresstypemap.dat`</i> Schema namespace prefix name preference for wsdl2h
6328 - <i>`graph.h`</i> Graph data binding (tree, digraph, cyclic graph)
6329 - <i>`graph.cpp`</i> Test graph serialization as tree, digraph, and cyclic
6330 
6331 🔝 [Back to table of contents](#)
6332 
6333 Generated files
6334 ---------------
6335 
6336 - <i>`address.h`</i> data binding interface generated from address.xsd
6337 - <i>`addressStub.h`</i> C++ data binding definitions
6338 - <i>`addressH.h`</i> Serializers
6339 - <i>`addressC.cpp`</i> Serializers
6340 - <i>`address.xml`</i> Address book data generated by address app
6341 - <i>`graphStub.h`</i> C++ data binding definitions
6342 - <i>`graphH.h`</i> Serializers
6343 - <i>`graphC.cpp`</i> Serializers
6344 - <i>`g.xsd`</i> XSD schema with <i>`g:Graph`</i> complexType
6345 - <i>`g.nsmap`</i> xmlns bindings namespace mapping table
6346 
6347 🔝 [Back to table of contents](#)
6348 
6349 Build steps
6350 -----------
6351 
6352 Building the AddressBook example:
6353 
6354  wsdl2h -g -taddresstypemap.dat address.xsd
6355  soapcpp2 -0 -C -S -paddress -I../../import address.h
6356  c++ -I../.. address.cpp addressC.cpp -o address -lgsoap++
6357 
6358 Using <b>`wsdl2h -g -taddresstypemap.dat`</b> option <b>`-g`</b> produces
6359 bindings for global (root) elements in addition to types and option
6360 <b>`-taddresstypemap.dat`</b> specifies a mapping file, see further below.
6361 
6362 In this case the root element <i>`a:address-book`</i> is bound to `_a__address_book`.
6363 The complexType <i>`a:address`</i> is bound to class `a__address`, which is also the
6364 type of `_a__address_book`. This option is not required, but allows you to use
6365 global element tag names when referring to their serializers, instead of their
6366 type name. Using <b>`soapcpp2 -0 -C -S -paddress`</b> option <b>`-0`</b> removes the
6367 SOAP protocol and the combination of the two options <b>`-C`</b> and
6368 <b>`-S`</b> removes client and server code generation (using option <b>`-C`</b>
6369 alone generates client code and using option <b>`-S`</b> alone generates server
6370 code). Option <b>`-paddress`</b> renames the output <i>`soap`</i>-prefixed files to
6371 <i>`address`</i>-prefixed files.
6372 
6373 See the <i>`address.cpp`</i> implementation and [related pages](pages.html).
6374 
6375 The <i>`addresstypemap.dat`</i> file specifies the XML namespace prefix for the
6376 bindings:
6377 
6378  # Bind the address book schema namespace to prefix 'a'
6379 
6380  a = "urn:address-book-example"
6381 
6382  # By default the xsd:dateTime schema type is translated to time_t
6383  # To map xsd:dateTime to struct tm, enable the following line:
6384 
6385  # xsd__dateTime = #import "../../custom/struct_tm.h"
6386 
6387  # ... and compile/link with custom/struct_tm.c
6388 
6389 The DOB field is a <i>`xsd:dateTime`</i>, which is bound to `time_t` by default. To
6390 change this to `struct tm`, enable the import of the `xsd__dateTime` custom
6391 serializer by uncommenting the definition of `xsd__dateTime` in
6392 <i>`addresstypemap.dat`</i>. Then change `soap_dateTime2s` to `soap_xsd__dateTime2s`
6393 in the code.
6394 
6395 Building the graph serialization example:
6396 
6397  soapcpp2 -C -S -pgraph -I../../import graph.h
6398  c++ -I../.. graph.cpp graphC.cpp -o graph -lgsoap++
6399 
6400 To compile without using the <b>`-lgsoap++`</b> library: simply compile
6401 <i>`stdsoap2.cpp`</i> together with the above.
6402 
6403 🔝 [Back to table of contents](#)
6404 
6405 Usage
6406 -----
6407 
6408 To execute the AddressBook example:
6409 
6410  ./address
6411 
6412 To execute the Graph serialization example:
6413 
6414  ./graph
6415