xref: /freebsd/contrib/expat/doc/reference.html (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1<?xml version="1.0" encoding="iso-8859-1"?>
2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
3                      "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
4<html>
5<head>
6<!-- Copyright 1999,2000 Clark Cooper <coopercc@netheaven.com>
7     All rights reserved.
8     This is free software. You may distribute or modify according to
9     the terms of the MIT/X License -->
10  <title>Expat XML Parser</title>
11  <meta name="author" content="Clark Cooper, coopercc@netheaven.com" />
12  <meta http-equiv="Content-Style-Type" content="text/css" />
13  <link href="style.css" rel="stylesheet" type="text/css" />
14</head>
15<body>
16  <table cellspacing="0" cellpadding="0" width="100%">
17    <tr>
18      <td class="corner"><img src="expat.png" alt="(Expat logo)" /></td>
19      <td class="banner"><h1>The Expat XML Parser</h1></td>
20    </tr>
21    <tr>
22      <td class="releaseno">Release 2.0.1</td>
23      <td></td>
24    </tr>
25  </table>
26<div class="content">
27
28<p>Expat is a library, written in C, for parsing XML documents. It's
29the underlying XML parser for the open source Mozilla project, Perl's
30<code>XML::Parser</code>, Python's <code>xml.parsers.expat</code>, and
31other open-source XML parsers.</p>
32
33<p>This library is the creation of James Clark, who's also given us
34groff (an nroff look-alike), Jade (an implemention of ISO's DSSSL
35stylesheet language for SGML), XP (a Java XML parser package), XT (a
36Java XSL engine).  James was also the technical lead on the XML
37Working Group at W3C that produced the XML specification.</p>
38
39<p>This is free software, licensed under the <a
40href="../COPYING">MIT/X Consortium license</a>. You may download it
41from <a href="http://www.libexpat.org/">the Expat home page</a>.
42</p>
43
44<p>The bulk of this document was originally commissioned as an article
45by <a href="http://www.xml.com/">XML.com</a>. They graciously allowed
46Clark Cooper to retain copyright and to distribute it with Expat.
47This version has been substantially extended to include documentation
48on features which have been added since the original article was
49published, and additional information on using the original
50interface.</p>
51
52<hr />
53<h2>Table of Contents</h2>
54<ul>
55  <li><a href="#overview">Overview</a></li>
56  <li><a href="#building">Building and Installing</a></li>
57  <li><a href="#using">Using Expat</a></li>
58  <li><a href="#reference">Reference</a>
59  <ul>
60    <li><a href="#creation">Parser Creation Functions</a>
61    <ul>
62      <li><a href="#XML_ParserCreate">XML_ParserCreate</a></li>
63      <li><a href="#XML_ParserCreateNS">XML_ParserCreateNS</a></li>
64      <li><a href="#XML_ParserCreate_MM">XML_ParserCreate_MM</a></li>
65      <li><a href="#XML_ExternalEntityParserCreate">XML_ExternalEntityParserCreate</a></li>
66      <li><a href="#XML_ParserFree">XML_ParserFree</a></li>
67      <li><a href="#XML_ParserReset">XML_ParserReset</a></li>
68    </ul>
69    </li>
70    <li><a href="#parsing">Parsing Functions</a>
71    <ul>
72      <li><a href="#XML_Parse">XML_Parse</a></li>
73      <li><a href="#XML_ParseBuffer">XML_ParseBuffer</a></li>
74      <li><a href="#XML_GetBuffer">XML_GetBuffer</a></li>
75      <li><a href="#XML_StopParser">XML_StopParser</a></li>
76      <li><a href="#XML_ResumeParser">XML_ResumeParser</a></li>
77      <li><a href="#XML_GetParsingStatus">XML_GetParsingStatus</a></li>
78    </ul>
79    </li>
80    <li><a href="#setting">Handler Setting Functions</a>
81    <ul>
82      <li><a href="#XML_SetStartElementHandler">XML_SetStartElementHandler</a></li>
83      <li><a href="#XML_SetEndElementHandler">XML_SetEndElementHandler</a></li>
84      <li><a href="#XML_SetElementHandler">XML_SetElementHandler</a></li>
85      <li><a href="#XML_SetCharacterDataHandler">XML_SetCharacterDataHandler</a></li>
86      <li><a href="#XML_SetProcessingInstructionHandler">XML_SetProcessingInstructionHandler</a></li>
87      <li><a href="#XML_SetCommentHandler">XML_SetCommentHandler</a></li>
88      <li><a href="#XML_SetStartCdataSectionHandler">XML_SetStartCdataSectionHandler</a></li>
89      <li><a href="#XML_SetEndCdataSectionHandler">XML_SetEndCdataSectionHandler</a></li>
90      <li><a href="#XML_SetCdataSectionHandler">XML_SetCdataSectionHandler</a></li>
91      <li><a href="#XML_SetDefaultHandler">XML_SetDefaultHandler</a></li>
92      <li><a href="#XML_SetDefaultHandlerExpand">XML_SetDefaultHandlerExpand</a></li>
93      <li><a href="#XML_SetExternalEntityRefHandler">XML_SetExternalEntityRefHandler</a></li>
94      <li><a href="#XML_SetExternalEntityRefHandlerArg">XML_SetExternalEntityRefHandlerArg</a></li>
95      <li><a href="#XML_SetSkippedEntityHandler">XML_SetSkippedEntityHandler</a></li>
96      <li><a href="#XML_SetUnknownEncodingHandler">XML_SetUnknownEncodingHandler</a></li>
97      <li><a href="#XML_SetStartNamespaceDeclHandler">XML_SetStartNamespaceDeclHandler</a></li>
98      <li><a href="#XML_SetEndNamespaceDeclHandler">XML_SetEndNamespaceDeclHandler</a></li>
99      <li><a href="#XML_SetNamespaceDeclHandler">XML_SetNamespaceDeclHandler</a></li>
100      <li><a href="#XML_SetXmlDeclHandler">XML_SetXmlDeclHandler</a></li>
101      <li><a href="#XML_SetStartDoctypeDeclHandler">XML_SetStartDoctypeDeclHandler</a></li>
102      <li><a href="#XML_SetEndDoctypeDeclHandler">XML_SetEndDoctypeDeclHandler</a></li>
103      <li><a href="#XML_SetDoctypeDeclHandler">XML_SetDoctypeDeclHandler</a></li>
104      <li><a href="#XML_SetElementDeclHandler">XML_SetElementDeclHandler</a></li>
105      <li><a href="#XML_SetAttlistDeclHandler">XML_SetAttlistDeclHandler</a></li>
106      <li><a href="#XML_SetEntityDeclHandler">XML_SetEntityDeclHandler</a></li>
107      <li><a href="#XML_SetUnparsedEntityDeclHandler">XML_SetUnparsedEntityDeclHandler</a></li>
108      <li><a href="#XML_SetNotationDeclHandler">XML_SetNotationDeclHandler</a></li>
109      <li><a href="#XML_SetNotStandaloneHandler">XML_SetNotStandaloneHandler</a></li>
110    </ul>
111    </li>
112    <li><a href="#position">Parse Position and Error Reporting Functions</a>
113    <ul>
114      <li><a href="#XML_GetErrorCode">XML_GetErrorCode</a></li>
115      <li><a href="#XML_ErrorString">XML_ErrorString</a></li>
116      <li><a href="#XML_GetCurrentByteIndex">XML_GetCurrentByteIndex</a></li>
117      <li><a href="#XML_GetCurrentLineNumber">XML_GetCurrentLineNumber</a></li>
118      <li><a href="#XML_GetCurrentColumnNumber">XML_GetCurrentColumnNumber</a></li>
119      <li><a href="#XML_GetCurrentByteCount">XML_GetCurrentByteCount</a></li>
120      <li><a href="#XML_GetInputContext">XML_GetInputContext</a></li>
121    </ul>
122    </li>
123    <li><a href="#miscellaneous">Miscellaneous Functions</a>
124    <ul>
125      <li><a href="#XML_SetUserData">XML_SetUserData</a></li>
126      <li><a href="#XML_GetUserData">XML_GetUserData</a></li>
127      <li><a href="#XML_UseParserAsHandlerArg">XML_UseParserAsHandlerArg</a></li>
128      <li><a href="#XML_SetBase">XML_SetBase</a></li>
129      <li><a href="#XML_GetBase">XML_GetBase</a></li>
130      <li><a href="#XML_GetSpecifiedAttributeCount">XML_GetSpecifiedAttributeCount</a></li>
131      <li><a href="#XML_GetIdAttributeIndex">XML_GetIdAttributeIndex</a></li>
132      <li><a href="#XML_SetEncoding">XML_SetEncoding</a></li>
133      <li><a href="#XML_SetParamEntityParsing">XML_SetParamEntityParsing</a></li>
134      <li><a href="#XML_UseForeignDTD">XML_UseForeignDTD</a></li>
135      <li><a href="#XML_SetReturnNSTriplet">XML_SetReturnNSTriplet</a></li>
136      <li><a href="#XML_DefaultCurrent">XML_DefaultCurrent</a></li>
137      <li><a href="#XML_ExpatVersion">XML_ExpatVersion</a></li>
138      <li><a href="#XML_ExpatVersionInfo">XML_ExpatVersionInfo</a></li>
139      <li><a href="#XML_GetFeatureList">XML_GetFeatureList</a></li>
140      <li><a href="#XML_FreeContentModel">XML_FreeContentModel</a></li>
141      <li><a href="#XML_MemMalloc">XML_MemMalloc</a></li>
142      <li><a href="#XML_MemRealloc">XML_MemRealloc</a></li>
143      <li><a href="#XML_MemFree">XML_MemFree</a></li>
144    </ul>
145    </li>
146  </ul>
147  </li>
148</ul>
149
150<hr />
151<h2><a name="overview">Overview</a></h2>
152
153<p>Expat is a stream-oriented parser. You register callback (or
154handler) functions with the parser and then start feeding it the
155document.  As the parser recognizes parts of the document, it will
156call the appropriate handler for that part (if you've registered one.)
157The document is fed to the parser in pieces, so you can start parsing
158before you have all the document. This also allows you to parse really
159huge documents that won't fit into memory.</p>
160
161<p>Expat can be intimidating due to the many kinds of handlers and
162options you can set. But you only need to learn four functions in
163order to do 90% of what you'll want to do with it:</p>
164
165<dl>
166
167<dt><code><a href= "#XML_ParserCreate"
168             >XML_ParserCreate</a></code></dt>
169  <dd>Create a new parser object.</dd>
170
171<dt><code><a href= "#XML_SetElementHandler"
172             >XML_SetElementHandler</a></code></dt>
173  <dd>Set handlers for start and end tags.</dd>
174
175<dt><code><a href= "#XML_SetCharacterDataHandler"
176             >XML_SetCharacterDataHandler</a></code></dt>
177  <dd>Set handler for text.</dd>
178
179<dt><code><a href= "#XML_Parse"
180             >XML_Parse</a></code></dt>
181  <dd>Pass a buffer full of document to the parser</dd>
182</dl>
183
184<p>These functions and others are described in the <a
185href="#reference">reference</a> part of this document. The reference
186section also describes in detail the parameters passed to the
187different types of handlers.</p>
188
189<p>Let's look at a very simple example program that only uses 3 of the
190above functions (it doesn't need to set a character handler.) The
191program <a href="../examples/outline.c">outline.c</a> prints an
192element outline, indenting child elements to distinguish them from the
193parent element that contains them. The start handler does all the
194work.  It prints two indenting spaces for every level of ancestor
195elements, then it prints the element and attribute
196information. Finally it increments the global <code>Depth</code>
197variable.</p>
198
199<pre class="eg">
200int Depth;
201
202void XMLCALL
203start(void *data, const char *el, const char **attr) {
204  int i;
205
206  for (i = 0; i &lt; Depth; i++)
207    printf("  ");
208
209  printf("%s", el);
210
211  for (i = 0; attr[i]; i += 2) {
212    printf(" %s='%s'", attr[i], attr[i + 1]);
213  }
214
215  printf("\n");
216  Depth++;
217}  /* End of start handler */
218</pre>
219
220<p>The end tag simply does the bookkeeping work of decrementing
221<code>Depth</code>.</p>
222<pre class="eg">
223void XMLCALL
224end(void *data, const char *el) {
225  Depth--;
226}  /* End of end handler */
227</pre>
228
229<p>Note the <code>XMLCALL</code> annotation used for the callbacks.
230This is used to ensure that the Expat and the callbacks are using the
231same calling convention in case the compiler options used for Expat
232itself and the client code are different.  Expat tries not to care
233what the default calling convention is, though it may require that it
234be compiled with a default convention of "cdecl" on some platforms.
235For code which uses Expat, however, the calling convention is
236specified by the <code>XMLCALL</code> annotation on most platforms;
237callbacks should be defined using this annotation.</p>
238
239<p>The <code>XMLCALL</code> annotation was added in Expat 1.95.7, but
240existing working Expat applications don't need to add it (since they
241are already using the "cdecl" calling convention, or they wouldn't be
242working).  The annotation is only needed if the default calling
243convention may be something other than "cdecl".  To use the annotation
244safely with older versions of Expat, you can conditionally define it
245<em>after</em> including Expat's header file:</p>
246
247<pre class="eg">
248#include &lt;expat.h&gt;
249
250#ifndef XMLCALL
251#if defined(_MSC_EXTENSIONS) &amp;&amp; !defined(__BEOS__) &amp;&amp; !defined(__CYGWIN__)
252#define XMLCALL __cdecl
253#elif defined(__GNUC__)
254#define XMLCALL __attribute__((cdecl))
255#else
256#define XMLCALL
257#endif
258#endif
259</pre>
260
261<p>After creating the parser, the main program just has the job of
262shoveling the document to the parser so that it can do its work.</p>
263
264<hr />
265<h2><a name="building">Building and Installing Expat</a></h2>
266
267<p>The Expat distribution comes as a compressed (with GNU gzip) tar
268file.  You may download the latest version from <a href=
269"http://sourceforge.net/projects/expat/" >Source Forge</a>.  After
270unpacking this, cd into the directory. Then follow either the Win32
271directions or Unix directions below.</p>
272
273<h3>Building under Win32</h3>
274
275<p>If you're using the GNU compiler under cygwin, follow the Unix
276directions in the next section. Otherwise if you have Microsoft's
277Developer Studio installed, then from Windows Explorer double-click on
278"expat.dsp" in the lib directory and build and install in the usual
279manner.</p>
280
281<p>Alternatively, you may download the Win32 binary package that
282contains the "expat.h" include file and a pre-built DLL.</p>
283
284<h3>Building under Unix (or GNU)</h3>
285
286<p>First you'll need to run the configure shell script in order to
287configure the Makefiles and headers for your system.</p>
288
289<p>If you're happy with all the defaults that configure picks for you,
290and you have permission on your system to install into /usr/local, you
291can install Expat with this sequence of commands:</p>
292
293<pre class="eg">
294./configure
295make
296make install
297</pre>
298
299<p>There are some options that you can provide to this script, but the
300only one we'll mention here is the <code>--prefix</code> option. You
301can find out all the options available by running configure with just
302the <code>--help</code> option.</p>
303
304<p>By default, the configure script sets things up so that the library
305gets installed in <code>/usr/local/lib</code> and the associated
306header file in <code>/usr/local/include</code>.  But if you were to
307give the option, <code>--prefix=/home/me/mystuff</code>, then the
308library and header would get installed in
309<code>/home/me/mystuff/lib</code> and
310<code>/home/me/mystuff/include</code> respectively.</p>
311
312<h3>Configuring Expat Using the Pre-Processor</h3>
313
314<p>Expat's feature set can be configured using a small number of
315pre-processor definitions.  The definition of this symbols does not
316affect the set of entry points for Expat, only the behavior of the API
317and the definition of character types in the case of
318<code>XML_UNICODE_WCHAR_T</code>.  The symbols are:</p>
319
320<dl class="cpp-symbols">
321<dt>XML_DTD</dt>
322<dd>Include support for using and reporting DTD-based content.  If
323this is defined, default attribute values from an external DTD subset
324are reported and attribute value normalization occurs based on the
325type of attributes defined in the external subset.  Without
326this, Expat has a smaller memory footprint and can be faster, but will
327not load external entities or process conditional sections.  This does
328not affect the set of functions available in the API.</dd>
329
330<dt>XML_NS</dt>
331<dd>When defined, support for the <cite><a href=
332"http://www.w3.org/TR/REC-xml-names/" >Namespaces in XML</a></cite>
333specification is included.</dd>
334
335<dt>XML_UNICODE</dt>
336<dd>When defined, character data reported to the application is
337encoded in UTF-16 using wide characters of the type
338<code>XML_Char</code>.  This is implied if
339<code>XML_UNICODE_WCHAR_T</code> is defined.</dd>
340
341<dt>XML_UNICODE_WCHAR_T</dt>
342<dd>If defined, causes the <code>XML_Char</code> character type to be
343defined using the <code>wchar_t</code> type; otherwise, <code>unsigned
344short</code> is used.  Defining this implies
345<code>XML_UNICODE</code>.</dd>
346
347<dt>XML_LARGE_SIZE</dt>
348<dd>If defined, causes the <code>XML_Size</code> and <code>XML_Index</code>
349integer types to be at least 64 bits in size. This is intended to support
350processing of very large input streams, where the return values of
351<code><a href="#XML_GetCurrentByteIndex" >XML_GetCurrentByteIndex</a></code>,
352<code><a href="#XML_GetCurrentLineNumber" >XML_GetCurrentLineNumber</a></code> and
353<code><a href="#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>
354could overflow. It may not be supported by all compilers, and is turned
355off by default.</dd>
356
357<dt>XML_CONTEXT_BYTES</dt>
358<dd>The number of input bytes of markup context which the parser will
359ensure are available for reporting via <code><a href=
360"#XML_GetInputContext" >XML_GetInputContext</a></code>.  This is
361normally set to 1024, and must be set to a positive interger.  If this
362is not defined, the input context will not be available and <code><a
363href= "#XML_GetInputContext" >XML_GetInputContext</a></code> will
364always report NULL.  Without this, Expat has a smaller memory
365footprint and can be faster.</dd>
366
367<dt>XML_STATIC</dt>
368<dd>On Windows, this should be set if Expat is going to be linked
369statically with the code that calls it; this is required to get all
370the right MSVC magic annotations correct.  This is ignored on other
371platforms.</dd>
372</dl>
373
374<hr />
375<h2><a name="using">Using Expat</a></h2>
376
377<h3>Compiling and Linking Against Expat</h3>
378
379<p>Unless you installed Expat in a location not expected by your
380compiler and linker, all you have to do to use Expat in your programs
381is to include the Expat header (<code>#include &lt;expat.h&gt;</code>)
382in your files that make calls to it and to tell the linker that it
383needs to link against the Expat library.  On Unix systems, this would
384usually be done with the <code>-lexpat</code> argument.  Otherwise,
385you'll need to tell the compiler where to look for the Expat header
386and the linker where to find the Expat library.  You may also need to
387take steps to tell the operating system where to find this library at
388run time.</p>
389
390<p>On a Unix-based system, here's what a Makefile might look like when
391Expat is installed in a standard location:</p>
392
393<pre class="eg">
394CC=cc
395LDFLAGS=
396LIBS= -lexpat
397xmlapp: xmlapp.o
398        $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
399</pre>
400
401<p>If you installed Expat in, say, <code>/home/me/mystuff</code>, then
402the Makefile would look like this:</p>
403
404<pre class="eg">
405CC=cc
406CFLAGS= -I/home/me/mystuff/include
407LDFLAGS=
408LIBS= -L/home/me/mystuff/lib -lexpat
409xmlapp: xmlapp.o
410        $(CC) $(LDFLAGS) -o xmlapp xmlapp.o $(LIBS)
411</pre>
412
413<p>You'd also have to set the environment variable
414<code>LD_LIBRARY_PATH</code> to <code>/home/me/mystuff/lib</code> (or
415to <code>${LD_LIBRARY_PATH}:/home/me/mystuff/lib</code> if
416LD_LIBRARY_PATH already has some directories in it) in order to run
417your application.</p>
418
419<h3>Expat Basics</h3>
420
421<p>As we saw in the example in the overview, the first step in parsing
422an XML document with Expat is to create a parser object. There are <a
423href="#creation">three functions</a> in the Expat API for creating a
424parser object.  However, only two of these (<code><a href=
425"#XML_ParserCreate" >XML_ParserCreate</a></code> and <code><a href=
426"#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>) can be used for
427constructing a parser for a top-level document.  The object returned
428by these functions is an opaque pointer (i.e. "expat.h" declares it as
429void *) to data with further internal structure. In order to free the
430memory associated with this object you must call <code><a href=
431"#XML_ParserFree" >XML_ParserFree</a></code>. Note that if you have
432provided any <a href="#userdata">user data</a> that gets stored in the
433parser, then your application is responsible for freeing it prior to
434calling <code>XML_ParserFree</code>.</p>
435
436<p>The objects returned by the parser creation functions are good for
437parsing only one XML document or external parsed entity. If your
438application needs to parse many XML documents, then it needs to create
439a parser object for each one. The best way to deal with this is to
440create a higher level object that contains all the default
441initialization you want for your parser objects.</p>
442
443<p>Walking through a document hierarchy with a stream oriented parser
444will require a good stack mechanism in order to keep track of current
445context.  For instance, to answer the simple question, "What element
446does this text belong to?" requires a stack, since the parser may have
447descended into other elements that are children of the current one and
448has encountered this text on the way out.</p>
449
450<p>The things you're likely to want to keep on a stack are the
451currently opened element and it's attributes. You push this
452information onto the stack in the start handler and you pop it off in
453the end handler.</p>
454
455<p>For some tasks, it is sufficient to just keep information on what
456the depth of the stack is (or would be if you had one.) The outline
457program shown above presents one example. Another such task would be
458skipping over a complete element. When you see the start tag for the
459element you want to skip, you set a skip flag and record the depth at
460which the element started.  When the end tag handler encounters the
461same depth, the skipped element has ended and the flag may be
462cleared. If you follow the convention that the root element starts at
4631, then you can use the same variable for skip flag and skip
464depth.</p>
465
466<pre class="eg">
467void
468init_info(Parseinfo *info) {
469  info->skip = 0;
470  info->depth = 1;
471  /* Other initializations here */
472}  /* End of init_info */
473
474void XMLCALL
475rawstart(void *data, const char *el, const char **attr) {
476  Parseinfo *inf = (Parseinfo *) data;
477
478  if (! inf->skip) {
479    if (should_skip(inf, el, attr)) {
480      inf->skip = inf->depth;
481    }
482    else
483      start(inf, el, attr);     /* This does rest of start handling */
484  }
485
486  inf->depth++;
487}  /* End of rawstart */
488
489void XMLCALL
490rawend(void *data, const char *el) {
491  Parseinfo *inf = (Parseinfo *) data;
492
493  inf->depth--;
494
495  if (! inf->skip)
496    end(inf, el);              /* This does rest of end handling */
497
498  if (inf->skip == inf->depth)
499    inf->skip = 0;
500}  /* End rawend */
501</pre>
502
503<p>Notice in the above example the difference in how depth is
504manipulated in the start and end handlers. The end tag handler should
505be the mirror image of the start tag handler. This is necessary to
506properly model containment. Since, in the start tag handler, we
507incremented depth <em>after</em> the main body of start tag code, then
508in the end handler, we need to manipulate it <em>before</em> the main
509body.  If we'd decided to increment it first thing in the start
510handler, then we'd have had to decrement it last thing in the end
511handler.</p>
512
513<h3 id="userdata">Communicating between handlers</h3>
514
515<p>In order to be able to pass information between different handlers
516without using globals, you'll need to define a data structure to hold
517the shared variables. You can then tell Expat (with the <code><a href=
518"#XML_SetUserData" >XML_SetUserData</a></code> function) to pass a
519pointer to this structure to the handlers.  This is the first
520argument received by most handlers.  In the <a href="#reference"
521>reference section</a>, an argument to a callback function is named
522<code>userData</code> and have type <code>void *</code> if the user
523data is passed; it will have the type <code>XML_Parser</code> if the
524parser itself is passed.  When the parser is passed, the user data may
525be retrieved using <code><a href="#XML_GetUserData"
526>XML_GetUserData</a></code>.</p>
527
528<p>One common case where multiple calls to a single handler may need
529to communicate using an application data structure is the case when
530content passed to the character data handler (set by <code><a href=
531"#XML_SetCharacterDataHandler"
532>XML_SetCharacterDataHandler</a></code>) needs to be accumulated.  A
533common first-time mistake with any of the event-oriented interfaces to
534an XML parser is to expect all the text contained in an element to be
535reported by a single call to the character data handler.  Expat, like
536many other XML parsers, reports such data as a sequence of calls;
537there's no way to know when the end of the sequence is reached until a
538different callback is made.  A buffer referenced by the user data
539structure proves both an effective and convenient place to accumulate
540character data.</p>
541
542<!-- XXX example needed here -->
543
544
545<h3>XML Version</h3>
546
547<p>Expat is an XML 1.0 parser, and as such never complains based on
548the value of the <code>version</code> pseudo-attribute in the XML
549declaration, if present.</p>
550
551<p>If an application needs to check the version number (to support
552alternate processing), it should use the <code><a href=
553"#XML_SetXmlDeclHandler" >XML_SetXmlDeclHandler</a></code> function to
554set a handler that uses the information in the XML declaration to
555determine what to do.  This example shows how to check that only a
556version number of <code>"1.0"</code> is accepted:</p>
557
558<pre class="eg">
559static int wrong_version;
560static XML_Parser parser;
561
562static void XMLCALL
563xmldecl_handler(void            *userData,
564                const XML_Char  *version,
565                const XML_Char  *encoding,
566                int              standalone)
567{
568  static const XML_Char Version_1_0[] = {'1', '.', '0', 0};
569
570  int i;
571
572  for (i = 0; i &lt; (sizeof(Version_1_0) / sizeof(Version_1_0[0])); ++i) {
573    if (version[i] != Version_1_0[i]) {
574      wrong_version = 1;
575      /* also clear all other handlers: */
576      XML_SetCharacterDataHandler(parser, NULL);
577      ...
578      return;
579    }
580  }
581  ...
582}
583</pre>
584
585<h3>Namespace Processing</h3>
586
587<p>When the parser is created using the <code><a href=
588"#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>, function, Expat
589performs namespace processing. Under namespace processing, Expat
590consumes <code>xmlns</code> and <code>xmlns:...</code> attributes,
591which declare namespaces for the scope of the element in which they
592occur. This means that your start handler will not see these
593attributes.  Your application can still be informed of these
594declarations by setting namespace declaration handlers with <a href=
595"#XML_SetNamespaceDeclHandler"
596><code>XML_SetNamespaceDeclHandler</code></a>.</p>
597
598<p>Element type and attribute names that belong to a given namespace
599are passed to the appropriate handler in expanded form. By default
600this expanded form is a concatenation of the namespace URI, the
601separator character (which is the 2nd argument to <code><a href=
602"#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>), and the local
603name (i.e. the part after the colon). Names with undeclared prefixes
604are not well-formed when namespace processing is enabled, and will
605trigger an error. Unprefixed attribute names are never expanded,
606and unprefixed element names are only expanded when they are in the
607scope of a default namespace.</p>
608
609<p>However if <code><a href= "#XML_SetReturnNSTriplet"
610>XML_SetReturnNSTriplet</a></code> has been called with a non-zero
611<code>do_nst</code> parameter, then the expanded form for names with
612an explicit prefix is a concatenation of: URI, separator, local name,
613separator, prefix.</p>
614
615<p>You can set handlers for the start of a namespace declaration and
616for the end of a scope of a declaration with the <code><a href=
617"#XML_SetNamespaceDeclHandler" >XML_SetNamespaceDeclHandler</a></code>
618function.  The StartNamespaceDeclHandler is called prior to the start
619tag handler and the EndNamespaceDeclHandler is called after the
620corresponding end tag that ends the namespace's scope.  The namespace
621start handler gets passed the prefix and URI for the namespace.  For a
622default namespace declaration (xmlns='...'), the prefix will be null.
623The URI will be null for the case where the default namespace is being
624unset.  The namespace end handler just gets the prefix for the closing
625scope.</p>
626
627<p>These handlers are called for each declaration. So if, for
628instance, a start tag had three namespace declarations, then the
629StartNamespaceDeclHandler would be called three times before the start
630tag handler is called, once for each declaration.</p>
631
632<h3>Character Encodings</h3>
633
634<p>While XML is based on Unicode, and every XML processor is required
635to recognized UTF-8 and UTF-16 (1 and 2 byte encodings of Unicode),
636other encodings may be declared in XML documents or entities. For the
637main document, an XML declaration may contain an encoding
638declaration:</p>
639<pre>
640&lt;?xml version="1.0" encoding="ISO-8859-2"?&gt;
641</pre>
642
643<p>External parsed entities may begin with a text declaration, which
644looks like an XML declaration with just an encoding declaration:</p>
645<pre>
646&lt;?xml encoding="Big5"?&gt;
647</pre>
648
649<p>With Expat, you may also specify an encoding at the time of
650creating a parser. This is useful when the encoding information may
651come from a source outside the document itself (like a higher level
652protocol.)</p>
653
654<p><a name="builtin_encodings"></a>There are four built-in encodings
655in Expat:</p>
656<ul>
657<li>UTF-8</li>
658<li>UTF-16</li>
659<li>ISO-8859-1</li>
660<li>US-ASCII</li>
661</ul>
662
663<p>Anything else discovered in an encoding declaration or in the
664protocol encoding specified in the parser constructor, triggers a call
665to the <code>UnknownEncodingHandler</code>. This handler gets passed
666the encoding name and a pointer to an <code>XML_Encoding</code> data
667structure. Your handler must fill in this structure and return
668<code>XML_STATUS_OK</code> if it knows how to deal with the
669encoding. Otherwise the handler should return
670<code>XML_STATUS_ERROR</code>.  The handler also gets passed a pointer
671to an optional application data structure that you may indicate when
672you set the handler.</p>
673
674<p>Expat places restrictions on character encodings that it can
675support by filling in the <code>XML_Encoding</code> structure.
676include file:</p>
677<ol>
678<li>Every ASCII character that can appear in a well-formed XML document
679must be represented by a single byte, and that byte must correspond to
680it's ASCII encoding (except for the characters $@\^'{}~)</li>
681<li>Characters must be encoded in 4 bytes or less.</li>
682<li>All characters encoded must have Unicode scalar values less than or
683equal to 65535 (0xFFFF)<em>This does not apply to the built-in support
684for UTF-16 and UTF-8</em></li>
685<li>No character may be encoded by more that one distinct sequence of
686bytes</li>
687</ol>
688
689<p><code>XML_Encoding</code> contains an array of integers that
690correspond to the 1st byte of an encoding sequence. If the value in
691the array for a byte is zero or positive, then the byte is a single
692byte encoding that encodes the Unicode scalar value contained in the
693array. A -1 in this array indicates a malformed byte. If the value is
694-2, -3, or -4, then the byte is the beginning of a 2, 3, or 4 byte
695sequence respectively. Multi-byte sequences are sent to the convert
696function pointed at in the <code>XML_Encoding</code> structure. This
697function should return the Unicode scalar value for the sequence or -1
698if the sequence is malformed.</p>
699
700<p>One pitfall that novice Expat users are likely to fall into is that
701although Expat may accept input in various encodings, the strings that
702it passes to the handlers are always encoded in UTF-8 or UTF-16
703(depending on how Expat was compiled). Your application is responsible
704for any translation of these strings into other encodings.</p>
705
706<h3>Handling External Entity References</h3>
707
708<p>Expat does not read or parse external entities directly. Note that
709any external DTD is a special case of an external entity.  If you've
710set no <code>ExternalEntityRefHandler</code>, then external entity
711references are silently ignored. Otherwise, it calls your handler with
712the information needed to read and parse the external entity.</p>
713
714<p>Your handler isn't actually responsible for parsing the entity, but
715it is responsible for creating a subsidiary parser with <code><a href=
716"#XML_ExternalEntityParserCreate"
717>XML_ExternalEntityParserCreate</a></code> that will do the job. This
718returns an instance of <code>XML_Parser</code> that has handlers and
719other data structures initialized from the parent parser. You may then
720use <code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a
721href= "#XML_ParseBuffer">XML_ParseBuffer</a></code> calls against this
722parser.  Since external entities my refer to other external entities,
723your handler should be prepared to be called recursively.</p>
724
725<h3>Parsing DTDs</h3>
726
727<p>In order to parse parameter entities, before starting the parse,
728you must call <code><a href= "#XML_SetParamEntityParsing"
729>XML_SetParamEntityParsing</a></code> with one of the following
730arguments:</p>
731<dl>
732<dt><code>XML_PARAM_ENTITY_PARSING_NEVER</code></dt>
733<dd>Don't parse parameter entities or the external subset</dd>
734<dt><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></dt>
735<dd>Parse parameter entites and the external subset unless
736<code>standalone</code> was set to "yes" in the XML declaration.</dd>
737<dt><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></dt>
738<dd>Always parse parameter entities and the external subset</dd>
739</dl>
740
741<p>In order to read an external DTD, you also have to set an external
742entity reference handler as described above.</p>
743
744<h3 id="stop-resume">Temporarily Stopping Parsing</h3>
745
746<p>Expat 1.95.8 introduces a new feature: its now possible to stop
747parsing temporarily from within a handler function, even if more data
748has already been passed into the parser.  Applications for this
749include</p>
750
751<ul>
752  <li>Supporting the <a href= "http://www.w3.org/TR/xinclude/"
753  >XInclude</a> specification.</li>
754
755  <li>Delaying further processing until additional information is
756  available from some other source.</li>
757
758  <li>Adjusting processor load as task priorities shift within an
759  application.</li>
760
761  <li>Stopping parsing completely (simply free or reset the parser
762  instead of resuming in the outer parsing loop).  This can be useful
763  if a application-domain error is found in the XML being parsed or if
764  the result of the parse is determined not to be useful after
765  all.</li>
766</ul>
767
768<p>To take advantage of this feature, the main parsing loop of an
769application needs to support this specifically.  It cannot be
770supported with a parsing loop compatible with Expat 1.95.7 or
771earlier (though existing loops will continue to work without
772supporting the stop/resume feature).</p>
773
774<p>An application that uses this feature for a single parser will have
775the rough structure (in pseudo-code):</p>
776
777<pre class="pseudocode">
778fd = open_input()
779p = create_parser()
780
781if parse_xml(p, fd) {
782  /* suspended */
783
784  int suspended = 1;
785
786  while (suspended) {
787    do_something_else()
788    if ready_to_resume() {
789      suspended = continue_parsing(p, fd);
790    }
791  }
792}
793</pre>
794
795<p>An application that may resume any of several parsers based on
796input (either from the XML being parsed or some other source) will
797certainly have more interesting control structures.</p>
798
799<p>This C function could be used for the <code>parse_xml</code>
800function mentioned in the pseudo-code above:</p>
801
802<pre class="eg">
803#define BUFF_SIZE 10240
804
805/* Parse a document from the open file descriptor 'fd' until the parse
806   is complete (the document has been completely parsed, or there's
807   been an error), or the parse is stopped.  Return non-zero when
808   the parse is merely suspended.
809*/
810int
811parse_xml(XML_Parser p, int fd)
812{
813  for (;;) {
814    int last_chunk;
815    int bytes_read;
816    enum XML_Status status;
817
818    void *buff = XML_GetBuffer(p, BUFF_SIZE);
819    if (buff == NULL) {
820      /* handle error... */
821      return 0;
822    }
823    bytes_read = read(fd, buff, BUFF_SIZE);
824    if (bytes_read &lt; 0) {
825      /* handle error... */
826      return 0;
827    }
828    status = XML_ParseBuffer(p, bytes_read, bytes_read == 0);
829    switch (status) {
830      case XML_STATUS_ERROR:
831        /* handle error... */
832        return 0;
833      case XML_STATUS_SUSPENDED:
834        return 1;
835    }
836    if (bytes_read == 0)
837      return 0;
838  }
839}
840</pre>
841
842<p>The corresponding <code>continue_parsing</code> function is
843somewhat simpler, since it only need deal with the return code from
844<code><a href= "#XML_ResumeParser">XML_ResumeParser</a></code>; it can
845delegate the input handling to the <code>parse_xml</code>
846function:</p>
847
848<pre class="eg">
849/* Continue parsing a document which had been suspended.  The 'p' and
850   'fd' arguments are the same as passed to parse_xml().  Return
851   non-zero when the parse is suspended.
852*/
853int
854continue_parsing(XML_Parser p, int fd)
855{
856  enum XML_Status status = XML_ResumeParser(p);
857  switch (status) {
858    case XML_STATUS_ERROR:
859      /* handle error... */
860      return 0;
861    case XML_ERROR_NOT_SUSPENDED:
862      /* handle error... */
863      return 0;.
864    case XML_STATUS_SUSPENDED:
865      return 1;
866  }
867  return parse_xml(p, fd);
868}
869</pre>
870
871<p>Now that we've seen what a mess the top-level parsing loop can
872become, what have we gained?  Very simply, we can now use the <code><a
873href= "#XML_StopParser" >XML_StopParser</a></code> function to stop
874parsing, without having to go to great lengths to avoid additional
875processing that we're expecting to ignore.  As a bonus, we get to stop
876parsing <em>temporarily</em>, and come back to it when we're
877ready.</p>
878
879<p>To stop parsing from a handler function, use the <code><a href=
880"#XML_StopParser" >XML_StopParser</a></code> function.  This function
881takes two arguments; the parser being stopped and a flag indicating
882whether the parse can be resumed in the future.</p>
883
884<!-- XXX really need more here -->
885
886
887<hr />
888<!-- ================================================================ -->
889
890<h2><a name="reference">Expat Reference</a></h2>
891
892<h3><a name="creation">Parser Creation</a></h3>
893
894<pre class="fcndec" id="XML_ParserCreate">
895XML_Parser XMLCALL
896XML_ParserCreate(const XML_Char *encoding);
897</pre>
898<div class="fcndef">
899Construct a new parser. If encoding is non-null, it specifies a
900character encoding to use for the document. This overrides the document
901encoding declaration. There are four built-in encodings:
902<ul>
903<li>US-ASCII</li>
904<li>UTF-8</li>
905<li>UTF-16</li>
906<li>ISO-8859-1</li>
907</ul>
908Any other value will invoke a call to the UnknownEncodingHandler.
909</div>
910
911<pre class="fcndec" id="XML_ParserCreateNS">
912XML_Parser XMLCALL
913XML_ParserCreateNS(const XML_Char *encoding,
914                   XML_Char sep);
915</pre>
916<div class="fcndef">
917Constructs a new parser that has namespace processing in effect. Namespace
918expanded element names and attribute names are returned as a concatenation
919of the namespace URI, <em>sep</em>, and the local part of the name. This
920means that you should pick a character for <em>sep</em> that can't be
921part of a legal URI. There is a special case when <em>sep</em> is the null
922character <code>'\0'</code>: the namespace URI and the local part will be
923concatenated without any separator - this is intended to support RDF processors.
924It is a programming error to use the null separator with
925<a href= "#XML_SetReturnNSTriplet">namespace triplets</a>.</div>
926
927<pre class="fcndec" id="XML_ParserCreate_MM">
928XML_Parser XMLCALL
929XML_ParserCreate_MM(const XML_Char *encoding,
930                    const XML_Memory_Handling_Suite *ms,
931		    const XML_Char *sep);
932</pre>
933<pre class="signature">
934typedef struct {
935  void *(XMLCALL *malloc_fcn)(size_t size);
936  void *(XMLCALL *realloc_fcn)(void *ptr, size_t size);
937  void (XMLCALL *free_fcn)(void *ptr);
938} XML_Memory_Handling_Suite;
939</pre>
940<div class="fcndef">
941<p>Construct a new parser using the suite of memory handling functions
942specified in <code>ms</code>. If <code>ms</code> is NULL, then use the
943standard set of memory management functions. If <code>sep</code> is
944non NULL, then namespace processing is enabled in the created parser
945and the character pointed at by sep is used as the separator between
946the namespace URI and the local part of the name.</p>
947</div>
948
949<pre class="fcndec" id="XML_ExternalEntityParserCreate">
950XML_Parser XMLCALL
951XML_ExternalEntityParserCreate(XML_Parser p,
952                               const XML_Char *context,
953                               const XML_Char *encoding);
954</pre>
955<div class="fcndef">
956Construct a new <code>XML_Parser</code> object for parsing an external
957general entity. Context is the context argument passed in a call to a
958ExternalEntityRefHandler. Other state information such as handlers,
959user data, namespace processing is inherited from the parser passed as
960the 1st argument. So you shouldn't need to call any of the behavior
961changing functions on this parser (unless you want it to act
962differently than the parent parser).
963</div>
964
965<pre class="fcndec" id="XML_ParserFree">
966void XMLCALL
967XML_ParserFree(XML_Parser p);
968</pre>
969<div class="fcndef">
970Free memory used by the parser. Your application is responsible for
971freeing any memory associated with <a href="#userdata">user data</a>.
972</div>
973
974<pre class="fcndec" id="XML_ParserReset">
975XML_Bool XMLCALL
976XML_ParserReset(XML_Parser p,
977                const XML_Char *encoding);
978</pre>
979<div class="fcndef">
980Clean up the memory structures maintained by the parser so that it may
981be used again.  After this has been called, <code>parser</code> is
982ready to start parsing a new document.  All handlers are cleared from
983the parser, except for the unknownEncodingHandler.  The parser's external
984state is re-initialized except for the values of ns and ns_triplets.
985This function may not be used on a parser created using <code><a href=
986"#XML_ExternalEntityParserCreate" >XML_ExternalEntityParserCreate</a
987></code>; it will return <code>XML_FALSE</code> in that case.  Returns
988<code>XML_TRUE</code> on success.  Your application is responsible for
989dealing with any memory associated with <a href="#userdata">user data</a>.
990</div>
991
992<h3><a name="parsing">Parsing</a></h3>
993
994<p>To state the obvious: the three parsing functions <code><a href=
995"#XML_Parse" >XML_Parse</a></code>, <code><a href= "#XML_ParseBuffer">
996XML_ParseBuffer</a></code> and <code><a href= "#XML_GetBuffer">
997XML_GetBuffer</a></code> must not be called from within a handler
998unless they operate on a separate parser instance, that is, one that
999did not call the handler. For example, it is OK to call the parsing
1000functions from within an <code>XML_ExternalEntityRefHandler</code>,
1001if they apply to the parser created by
1002<code><a href= "#XML_ExternalEntityParserCreate"
1003>XML_ExternalEntityParserCreate</a></code>.</p>
1004
1005<p>Note: the <code>len</code> argument passed to these functions
1006should be considerably less than the maximum value for an integer,
1007as it could create an integer overflow situation if the added
1008lengths of a buffer and the unprocessed portion of the previous buffer
1009exceed the maximum integer value. Input data at the end of a buffer
1010will remain unprocessed if it is part of an XML token for which the
1011end is not part of that buffer.</p>
1012
1013<pre class="fcndec" id="XML_Parse">
1014enum XML_Status XMLCALL
1015XML_Parse(XML_Parser p,
1016          const char *s,
1017          int len,
1018          int isFinal);
1019</pre>
1020<pre class="signature">
1021enum XML_Status {
1022  XML_STATUS_ERROR = 0,
1023  XML_STATUS_OK = 1
1024};
1025</pre>
1026<div class="fcndef">
1027Parse some more of the document. The string <code>s</code> is a buffer
1028containing part (or perhaps all) of the document. The number of bytes of s
1029that are part of the document is indicated by <code>len</code>. This means
1030that <code>s</code> doesn't have to be null terminated. It also means that
1031if <code>len</code> is larger than the number of bytes in the block of
1032memory that <code>s</code> points at, then a memory fault is likely. The
1033<code>isFinal</code> parameter informs the parser that this is the last
1034piece of the document. Frequently, the last piece is empty (i.e.
1035<code>len</code> is zero.)
1036If a parse error occurred, it returns <code>XML_STATUS_ERROR</code>.
1037Otherwise it returns <code>XML_STATUS_OK</code> value.
1038</div>
1039
1040<pre class="fcndec" id="XML_ParseBuffer">
1041enum XML_Status XMLCALL
1042XML_ParseBuffer(XML_Parser p,
1043                int len,
1044                int isFinal);
1045</pre>
1046<div class="fcndef">
1047This is just like <code><a href= "#XML_Parse" >XML_Parse</a></code>,
1048except in this case Expat provides the buffer.  By obtaining the
1049buffer from Expat with the <code><a href= "#XML_GetBuffer"
1050>XML_GetBuffer</a></code> function, the application can avoid double
1051copying of the input.
1052</div>
1053
1054<pre class="fcndec" id="XML_GetBuffer">
1055void * XMLCALL
1056XML_GetBuffer(XML_Parser p,
1057              int len);
1058</pre>
1059<div class="fcndef">
1060Obtain a buffer of size <code>len</code> to read a piece of the document
1061into. A NULL value is returned if Expat can't allocate enough memory for
1062this buffer. This has to be called prior to every call to
1063<code><a href= "#XML_ParseBuffer" >XML_ParseBuffer</a></code>. A
1064typical use would look like this:
1065
1066<pre class="eg">
1067for (;;) {
1068  int bytes_read;
1069  void *buff = XML_GetBuffer(p, BUFF_SIZE);
1070  if (buff == NULL) {
1071    /* handle error */
1072  }
1073
1074  bytes_read = read(docfd, buff, BUFF_SIZE);
1075  if (bytes_read &lt; 0) {
1076    /* handle error */
1077  }
1078
1079  if (! XML_ParseBuffer(p, bytes_read, bytes_read == 0)) {
1080    /* handle parse error */
1081  }
1082
1083  if (bytes_read == 0)
1084    break;
1085}
1086</pre>
1087</div>
1088
1089<pre class="fcndec" id="XML_StopParser">
1090enum XML_Status XMLCALL
1091XML_StopParser(XML_Parser p,
1092               XML_Bool resumable);
1093</pre>
1094<div class="fcndef">
1095
1096<p>Stops parsing, causing <code><a href= "#XML_Parse"
1097>XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
1098>XML_ParseBuffer</a></code> to return.  Must be called from within a
1099call-back handler, except when aborting (when <code>resumable</code>
1100is <code>XML_FALSE</code>) an already suspended parser.  Some
1101call-backs may still follow because they would otherwise get
1102lost, including
1103<ul>
1104  <li> the end element handler for empty elements when stopped in the
1105       start element handler,</li>
1106  <li> the end namespace declaration handler when stopped in the end
1107       element handler,</li>
1108  <li> the character data handler when stopped in the character data handler
1109       while making multiple call-backs on a contiguous chunk of characters,</li>
1110</ul>
1111and possibly others.</p>
1112
1113<p>This can be called from most handlers, including DTD related
1114call-backs, except when parsing an external parameter entity and
1115<code>resumable</code> is <code>XML_TRUE</code>.  Returns
1116<code>XML_STATUS_OK</code> when successful,
1117<code>XML_STATUS_ERROR</code> otherwise.  The possible error codes
1118are:</p>
1119<dl>
1120  <dt><code>XML_ERROR_SUSPENDED</code></dt>
1121  <dd>when suspending an already suspended parser.</dd>
1122  <dt><code>XML_ERROR_FINISHED</code></dt>
1123  <dd>when the parser has already finished.</dd>
1124  <dt><code>XML_ERROR_SUSPEND_PE</code></dt>
1125  <dd>when suspending while parsing an external PE.</dd>
1126</dl>
1127
1128<p>Since the stop/resume feature requires application support in the
1129outer parsing loop, it is an error to call this function for a parser
1130not being handled appropriately; see <a href= "#stop-resume"
1131>Temporarily Stopping Parsing</a> for more information.</p>
1132
1133<p>When <code>resumable</code> is <code>XML_TRUE</code> then parsing
1134is <em>suspended</em>, that is, <code><a href= "#XML_Parse"
1135>XML_Parse</a></code> and <code><a href= "#XML_ParseBuffer"
1136>XML_ParseBuffer</a></code> return <code>XML_STATUS_SUSPENDED</code>.
1137Otherwise, parsing is <em>aborted</em>, that is, <code><a href=
1138"#XML_Parse" >XML_Parse</a></code> and <code><a href=
1139"#XML_ParseBuffer" >XML_ParseBuffer</a></code> return
1140<code>XML_STATUS_ERROR</code> with error code
1141<code>XML_ERROR_ABORTED</code>.</p>
1142
1143<p><strong>Note:</strong>
1144This will be applied to the current parser instance only, that is, if
1145there is a parent parser then it will continue parsing when the
1146external entity reference handler returns.  It is up to the
1147implementation of that handler to call <code><a href=
1148"#XML_StopParser" >XML_StopParser</a></code> on the parent parser
1149(recursively), if one wants to stop parsing altogether.</p>
1150
1151<p>When suspended, parsing can be resumed by calling <code><a href=
1152"#XML_ResumeParser" >XML_ResumeParser</a></code>.</p>
1153
1154<p>New in Expat 1.95.8.</p>
1155</div>
1156
1157<pre class="fcndec" id="XML_ResumeParser">
1158enum XML_Status XMLCALL
1159XML_ResumeParser(XML_Parser p);
1160</pre>
1161<div class="fcndef">
1162<p>Resumes parsing after it has been suspended with <code><a href=
1163"#XML_StopParser" >XML_StopParser</a></code>.  Must not be called from
1164within a handler call-back.  Returns same status codes as <code><a
1165href= "#XML_Parse">XML_Parse</a></code> or <code><a href=
1166"#XML_ParseBuffer" >XML_ParseBuffer</a></code>.  An additional error
1167code, <code>XML_ERROR_NOT_SUSPENDED</code>, will be returned if the
1168parser was not currently suspended.</p>
1169
1170<p><strong>Note:</strong>
1171This must be called on the most deeply nested child parser instance
1172first, and on its parent parser only after the child parser has
1173finished, to be applied recursively until the document entity's parser
1174is restarted.  That is, the parent parser will not resume by itself
1175and it is up to the application to call <code><a href=
1176"#XML_ResumeParser" >XML_ResumeParser</a></code> on it at the
1177appropriate moment.</p>
1178
1179<p>New in Expat 1.95.8.</p>
1180</div>
1181
1182<pre class="fcndec" id="XML_GetParsingStatus">
1183void XMLCALL
1184XML_GetParsingStatus(XML_Parser p,
1185                     XML_ParsingStatus *status);
1186</pre>
1187<pre class="signature">
1188enum XML_Parsing {
1189  XML_INITIALIZED,
1190  XML_PARSING,
1191  XML_FINISHED,
1192  XML_SUSPENDED
1193};
1194
1195typedef struct {
1196  enum XML_Parsing parsing;
1197  XML_Bool finalBuffer;
1198} XML_ParsingStatus;
1199</pre>
1200<div class="fcndef">
1201<p>Returns status of parser with respect to being initialized,
1202parsing, finished, or suspended, and whether the final buffer is being
1203processed.  The <code>status</code> parameter <em>must not</em> be
1204NULL.</p>
1205
1206<p>New in Expat 1.95.8.</p>
1207</div>
1208
1209
1210<h3><a name="setting">Handler Setting</a></h3>
1211
1212<p>Although handlers are typically set prior to parsing and left alone, an
1213application may choose to set or change the handler for a parsing event
1214while the parse is in progress. For instance, your application may choose
1215to ignore all text not descended from a <code>para</code> element. One
1216way it could do this is to set the character handler when a para start tag
1217is seen, and unset it for the corresponding end tag.</p>
1218
1219<p>A handler may be <em>unset</em> by providing a NULL pointer to the
1220appropriate handler setter. None of the handler setting functions have
1221a return value.</p>
1222
1223<p>Your handlers will be receiving strings in arrays of type
1224<code>XML_Char</code>. This type is conditionally defined in expat.h as
1225either <code>char</code>, <code>wchar_t</code> or <code>unsigned short</code>.
1226The former implies UTF-8 encoding, the latter two imply UTF-16 encoding.
1227Note that you'll receive them in this form independent of the original
1228encoding of the document.</p>
1229
1230<div class="handler">
1231<pre class="setter" id="XML_SetStartElementHandler">
1232void XMLCALL
1233XML_SetStartElementHandler(XML_Parser p,
1234                           XML_StartElementHandler start);
1235</pre>
1236<pre class="signature">
1237typedef void
1238(XMLCALL *XML_StartElementHandler)(void *userData,
1239                                   const XML_Char *name,
1240                                   const XML_Char **atts);
1241</pre>
1242<p>Set handler for start (and empty) tags. Attributes are passed to the start
1243handler as a pointer to a vector of char pointers. Each attribute seen in
1244a start (or empty) tag occupies 2 consecutive places in this vector: the
1245attribute name followed by the attribute value. These pairs are terminated
1246by a null pointer.</p>
1247<p>Note that an empty tag generates a call to both start and end handlers
1248(in that order).</p>
1249</div>
1250
1251<div class="handler">
1252<pre class="setter" id="XML_SetEndElementHandler">
1253void XMLCALL
1254XML_SetEndElementHandler(XML_Parser p,
1255                         XML_EndElementHandler);
1256</pre>
1257<pre class="signature">
1258typedef void
1259(XMLCALL *XML_EndElementHandler)(void *userData,
1260                                 const XML_Char *name);
1261</pre>
1262<p>Set handler for end (and empty) tags. As noted above, an empty tag
1263generates a call to both start and end handlers.</p>
1264</div>
1265
1266<div class="handler">
1267<pre class="setter" id="XML_SetElementHandler">
1268void XMLCALL
1269XML_SetElementHandler(XML_Parser p,
1270                      XML_StartElementHandler start,
1271                      XML_EndElementHandler end);
1272</pre>
1273<p>Set handlers for start and end tags with one call.</p>
1274</div>
1275
1276<div class="handler">
1277<pre class="setter" id="XML_SetCharacterDataHandler">
1278void XMLCALL
1279XML_SetCharacterDataHandler(XML_Parser p,
1280                            XML_CharacterDataHandler charhndl)
1281</pre>
1282<pre class="signature">
1283typedef void
1284(XMLCALL *XML_CharacterDataHandler)(void *userData,
1285                                    const XML_Char *s,
1286                                    int len);
1287</pre>
1288<p>Set a text handler. The string your handler receives
1289is <em>NOT nul-terminated</em>. You have to use the length argument
1290to deal with the end of the string. A single block of contiguous text
1291free of markup may still result in a sequence of calls to this handler.
1292In other words, if you're searching for a pattern in the text, it may
1293be split across calls to this handler. Note: Setting this handler to NULL
1294may <em>NOT immediately</em> terminate call-backs if the parser is currently
1295processing such a single block of contiguous markup-free text, as the parser
1296will continue calling back until the end of the block is reached.</p>
1297</div>
1298
1299<div class="handler">
1300<pre class="setter" id="XML_SetProcessingInstructionHandler">
1301void XMLCALL
1302XML_SetProcessingInstructionHandler(XML_Parser p,
1303                                    XML_ProcessingInstructionHandler proc)
1304</pre>
1305<pre class="signature">
1306typedef void
1307(XMLCALL *XML_ProcessingInstructionHandler)(void *userData,
1308                                            const XML_Char *target,
1309                                            const XML_Char *data);
1310
1311</pre>
1312<p>Set a handler for processing instructions. The target is the first word
1313in the processing instruction. The data is the rest of the characters in
1314it after skipping all whitespace after the initial word.</p>
1315</div>
1316
1317<div class="handler">
1318<pre class="setter" id="XML_SetCommentHandler">
1319void XMLCALL
1320XML_SetCommentHandler(XML_Parser p,
1321                      XML_CommentHandler cmnt)
1322</pre>
1323<pre class="signature">
1324typedef void
1325(XMLCALL *XML_CommentHandler)(void *userData,
1326                              const XML_Char *data);
1327</pre>
1328<p>Set a handler for comments. The data is all text inside the comment
1329delimiters.</p>
1330</div>
1331
1332<div class="handler">
1333<pre class="setter" id="XML_SetStartCdataSectionHandler">
1334void XMLCALL
1335XML_SetStartCdataSectionHandler(XML_Parser p,
1336                                XML_StartCdataSectionHandler start);
1337</pre>
1338<pre class="signature">
1339typedef void
1340(XMLCALL *XML_StartCdataSectionHandler)(void *userData);
1341</pre>
1342<p>Set a handler that gets called at the beginning of a CDATA section.</p>
1343</div>
1344
1345<div class="handler">
1346<pre class="setter" id="XML_SetEndCdataSectionHandler">
1347void XMLCALL
1348XML_SetEndCdataSectionHandler(XML_Parser p,
1349                              XML_EndCdataSectionHandler end);
1350</pre>
1351<pre class="signature">
1352typedef void
1353(XMLCALL *XML_EndCdataSectionHandler)(void *userData);
1354</pre>
1355<p>Set a handler that gets called at the end of a CDATA section.</p>
1356</div>
1357
1358<div class="handler">
1359<pre class="setter" id="XML_SetCdataSectionHandler">
1360void XMLCALL
1361XML_SetCdataSectionHandler(XML_Parser p,
1362                           XML_StartCdataSectionHandler start,
1363                           XML_EndCdataSectionHandler end)
1364</pre>
1365<p>Sets both CDATA section handlers with one call.</p>
1366</div>
1367
1368<div class="handler">
1369<pre class="setter" id="XML_SetDefaultHandler">
1370void XMLCALL
1371XML_SetDefaultHandler(XML_Parser p,
1372                      XML_DefaultHandler hndl)
1373</pre>
1374<pre class="signature">
1375typedef void
1376(XMLCALL *XML_DefaultHandler)(void *userData,
1377                              const XML_Char *s,
1378                              int len);
1379</pre>
1380
1381<p>Sets a handler for any characters in the document which wouldn't
1382otherwise be handled. This includes both data for which no handlers
1383can be set (like some kinds of DTD declarations) and data which could
1384be reported but which currently has no handler set.  The characters
1385are passed exactly as they were present in the XML document except
1386that they will be encoded in UTF-8 or UTF-16. Line boundaries are not
1387normalized. Note that a byte order mark character is not passed to the
1388default handler. There are no guarantees about how characters are
1389divided between calls to the default handler: for example, a comment
1390might be split between multiple calls.  Setting the handler with
1391this call has the side effect of turning off expansion of references
1392to internally defined general entities. Instead these references are
1393passed to the default handler.</p>
1394
1395<p>See also <code><a
1396href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
1397</div>
1398
1399<div class="handler">
1400<pre class="setter" id="XML_SetDefaultHandlerExpand">
1401void XMLCALL
1402XML_SetDefaultHandlerExpand(XML_Parser p,
1403                            XML_DefaultHandler hndl)
1404</pre>
1405<pre class="signature">
1406typedef void
1407(XMLCALL *XML_DefaultHandler)(void *userData,
1408                              const XML_Char *s,
1409                              int len);
1410</pre>
1411<p>This sets a default handler, but doesn't inhibit the expansion of
1412internal entity references.  The entity reference will not be passed
1413to the default handler.</p>
1414
1415<p>See also <code><a
1416href="#XML_DefaultCurrent">XML_DefaultCurrent</a></code>.</p>
1417</div>
1418
1419<div class="handler">
1420<pre class="setter" id="XML_SetExternalEntityRefHandler">
1421void XMLCALL
1422XML_SetExternalEntityRefHandler(XML_Parser p,
1423                                XML_ExternalEntityRefHandler hndl)
1424</pre>
1425<pre class="signature">
1426typedef int
1427(XMLCALL *XML_ExternalEntityRefHandler)(XML_Parser p,
1428                                        const XML_Char *context,
1429                                        const XML_Char *base,
1430                                        const XML_Char *systemId,
1431                                        const XML_Char *publicId);
1432</pre>
1433<p>Set an external entity reference handler. This handler is also
1434called for processing an external DTD subset if parameter entity parsing
1435is in effect. (See <a href="#XML_SetParamEntityParsing">
1436<code>XML_SetParamEntityParsing</code></a>.)</p>
1437
1438<p>The <code>context</code> parameter specifies the parsing context in
1439the format expected by the <code>context</code> argument to <code><a
1440href="#XML_ExternalEntityParserCreate"
1441>XML_ExternalEntityParserCreate</a></code>.  <code>code</code> is
1442valid only until the handler returns, so if the referenced entity is
1443to be parsed later, it must be copied.  <code>context</code> is NULL
1444only when the entity is a parameter entity, which is how one can
1445differentiate between general and parameter entities.</p>
1446
1447<p>The <code>base</code> parameter is the base to use for relative
1448system identifiers.  It is set by <code><a
1449href="#XML_SetBase">XML_SetBase</a></code> and may be NULL. The
1450<code>publicId</code> parameter is the public id given in the entity
1451declaration and may be NULL.  <code>systemId</code> is the system
1452identifier specified in the entity declaration and is never NULL.</p>
1453
1454<p>There are a couple of ways in which this handler differs from
1455others.  First, this handler returns a status indicator (an
1456integer). <code>XML_STATUS_OK</code> should be returned for successful
1457handling of the external entity reference.  Returning
1458<code>XML_STATUS_ERROR</code> indicates failure, and causes the
1459calling parser to return an
1460<code>XML_ERROR_EXTERNAL_ENTITY_HANDLING</code> error.</p>
1461
1462<p>Second, instead of having the user data as its first argument, it
1463receives the parser that encountered the entity reference. This, along
1464with the context parameter, may be used as arguments to a call to
1465<code><a href= "#XML_ExternalEntityParserCreate"
1466>XML_ExternalEntityParserCreate</a></code>.  Using the returned
1467parser, the body of the external entity can be recursively parsed.</p>
1468
1469<p>Since this handler may be called recursively, it should not be saving
1470information into global or static variables.</p>
1471</div>
1472
1473<pre class="fcndec" id="XML_SetExternalEntityRefHandlerArg">
1474void XMLCALL
1475XML_SetExternalEntityRefHandlerArg(XML_Parser p,
1476                                   void *arg)
1477</pre>
1478<div class="fcndef">
1479<p>Set the argument passed to the ExternalEntityRefHandler.  If
1480<code>arg</code> is not NULL, it is the new value passed to the
1481handler set using <code><a href="#XML_SetExternalEntityRefHandler"
1482>XML_SetExternalEntityRefHandler</a></code>; if <code>arg</code> is
1483NULL, the argument passed to the handler function will be the parser
1484object itself.</p>
1485
1486<p><strong>Note:</strong>
1487The type of <code>arg</code> and the type of the first argument to the
1488ExternalEntityRefHandler do not match.  This function takes a
1489<code>void *</code> to be passed to the handler, while the handler
1490accepts an <code>XML_Parser</code>.  This is a historical accident,
1491but will not be corrected before Expat 2.0 (at the earliest) to avoid
1492causing compiler warnings for code that's known to work with this
1493API.  It is the responsibility of the application code to know the
1494actual type of the argument passed to the handler and to manage it
1495properly.</p>
1496</div>
1497
1498<div class="handler">
1499<pre class="setter" id="XML_SetSkippedEntityHandler">
1500void XMLCALL
1501XML_SetSkippedEntityHandler(XML_Parser p,
1502                            XML_SkippedEntityHandler handler)
1503</pre>
1504<pre class="signature">
1505typedef void
1506(XMLCALL *XML_SkippedEntityHandler)(void *userData,
1507                                    const XML_Char *entityName,
1508                                    int is_parameter_entity);
1509</pre>
1510<p>Set a skipped entity handler. This is called in two situations:</p>
1511<ol>
1512   <li>An entity reference is encountered for which no declaration
1513       has been read <em>and</em> this is not an error.</li>
1514   <li>An internal entity reference is read, but not expanded, because
1515       <a href="#XML_SetDefaultHandler"><code>XML_SetDefaultHandler</code></a>
1516	   has been called.</li>
1517</ol>
1518<p>The <code>is_parameter_entity</code> argument will be non-zero for
1519a parameter entity and zero for a general entity.</p> <p>Note: skipped
1520parameter entities in declarations and skipped general entities in
1521attribute values cannot be reported, because the event would be out of
1522sync with the reporting of the declarations or attribute values</p>
1523</div>
1524
1525<div class="handler">
1526<pre class="setter" id="XML_SetUnknownEncodingHandler">
1527void XMLCALL
1528XML_SetUnknownEncodingHandler(XML_Parser p,
1529                              XML_UnknownEncodingHandler enchandler,
1530			      void *encodingHandlerData)
1531</pre>
1532<pre class="signature">
1533typedef int
1534(XMLCALL *XML_UnknownEncodingHandler)(void *encodingHandlerData,
1535                                      const XML_Char *name,
1536                                      XML_Encoding *info);
1537
1538typedef struct {
1539  int map[256];
1540  void *data;
1541  int (XMLCALL *convert)(void *data, const char *s);
1542  void (XMLCALL *release)(void *data);
1543} XML_Encoding;
1544</pre>
1545<p>Set a handler to deal with encodings other than the <a
1546href="#builtin_encodings">built in set</a>. This should be done before
1547<code><a href= "#XML_Parse" >XML_Parse</a></code> or <code><a href=
1548"#XML_ParseBuffer" >XML_ParseBuffer</a></code> have been called on the
1549given parser.</p> <p>If the handler knows how to deal with an encoding
1550with the given name, it should fill in the <code>info</code> data
1551structure and return <code>XML_STATUS_OK</code>. Otherwise it
1552should return <code>XML_STATUS_ERROR</code>. The handler will be called
1553at most once per parsed (external) entity. The optional application
1554data pointer <code>encodingHandlerData</code> will be passed back to
1555the handler.</p>
1556
1557<p>The map array contains information for every possible possible leading
1558byte in a byte sequence. If the corresponding value is &gt;= 0, then it's
1559a single byte sequence and the byte encodes that Unicode value. If the
1560value is -1, then that byte is invalid as the initial byte in a sequence.
1561If the value is -n, where n is an integer &gt; 1, then n is the number of
1562bytes in the sequence and the actual conversion is accomplished by a
1563call to the function pointed at by convert. This function may return -1
1564if the sequence itself is invalid. The convert pointer may be null if
1565there are only single byte codes. The data parameter passed to the convert
1566function is the data pointer from <code>XML_Encoding</code>. The
1567string s is <em>NOT</em> nul-terminated and points at the sequence of
1568bytes to be converted.</p>
1569
1570<p>The function pointed at by <code>release</code> is called by the
1571parser when it is finished with the encoding. It may be NULL.</p>
1572</div>
1573
1574<div class="handler">
1575<pre class="setter" id="XML_SetStartNamespaceDeclHandler">
1576void XMLCALL
1577XML_SetStartNamespaceDeclHandler(XML_Parser p,
1578			         XML_StartNamespaceDeclHandler start);
1579</pre>
1580<pre class="signature">
1581typedef void
1582(XMLCALL *XML_StartNamespaceDeclHandler)(void *userData,
1583                                         const XML_Char *prefix,
1584                                         const XML_Char *uri);
1585</pre>
1586<p>Set a handler to be called when a namespace is declared. Namespace
1587declarations occur inside start tags. But the namespace declaration start
1588handler is called before the start tag handler for each namespace declared
1589in that start tag.</p>
1590</div>
1591
1592<div class="handler">
1593<pre class="setter" id="XML_SetEndNamespaceDeclHandler">
1594void XMLCALL
1595XML_SetEndNamespaceDeclHandler(XML_Parser p,
1596			       XML_EndNamespaceDeclHandler end);
1597</pre>
1598<pre class="signature">
1599typedef void
1600(XMLCALL *XML_EndNamespaceDeclHandler)(void *userData,
1601                                       const XML_Char *prefix);
1602</pre>
1603<p>Set a handler to be called when leaving the scope of a namespace
1604declaration. This will be called, for each namespace declaration,
1605after the handler for the end tag of the element in which the
1606namespace was declared.</p>
1607</div>
1608
1609<div class="handler">
1610<pre class="setter" id="XML_SetNamespaceDeclHandler">
1611void XMLCALL
1612XML_SetNamespaceDeclHandler(XML_Parser p,
1613                            XML_StartNamespaceDeclHandler start,
1614                            XML_EndNamespaceDeclHandler end)
1615</pre>
1616<p>Sets both namespace declaration handlers with a single call.</p>
1617</div>
1618
1619<div class="handler">
1620<pre class="setter" id="XML_SetXmlDeclHandler">
1621void XMLCALL
1622XML_SetXmlDeclHandler(XML_Parser p,
1623		      XML_XmlDeclHandler xmldecl);
1624</pre>
1625<pre class="signature">
1626typedef void
1627(XMLCALL *XML_XmlDeclHandler)(void            *userData,
1628                              const XML_Char  *version,
1629                              const XML_Char  *encoding,
1630                              int             standalone);
1631</pre>
1632<p>Sets a handler that is called for XML declarations and also for
1633text declarations discovered in external entities. The way to
1634distinguish is that the <code>version</code> parameter will be NULL
1635for text declarations. The <code>encoding</code> parameter may be NULL
1636for an XML declaration. The <code>standalone</code> argument will
1637contain -1, 0, or 1 indicating respectively that there was no
1638standalone parameter in the declaration, that it was given as no, or
1639that it was given as yes.</p>
1640</div>
1641
1642<div class="handler">
1643<pre class="setter" id="XML_SetStartDoctypeDeclHandler">
1644void XMLCALL
1645XML_SetStartDoctypeDeclHandler(XML_Parser p,
1646			       XML_StartDoctypeDeclHandler start);
1647</pre>
1648<pre class="signature">
1649typedef void
1650(XMLCALL *XML_StartDoctypeDeclHandler)(void           *userData,
1651                                       const XML_Char *doctypeName,
1652                                       const XML_Char *sysid,
1653                                       const XML_Char *pubid,
1654                                       int            has_internal_subset);
1655</pre>
1656<p>Set a handler that is called at the start of a DOCTYPE declaration,
1657before any external or internal subset is parsed. Both <code>sysid</code>
1658and <code>pubid</code> may be NULL. The <code>has_internal_subset</code>
1659will be non-zero if the DOCTYPE declaration has an internal subset.</p>
1660</div>
1661
1662<div class="handler">
1663<pre class="setter" id="XML_SetEndDoctypeDeclHandler">
1664void XMLCALL
1665XML_SetEndDoctypeDeclHandler(XML_Parser p,
1666			     XML_EndDoctypeDeclHandler end);
1667</pre>
1668<pre class="signature">
1669typedef void
1670(XMLCALL *XML_EndDoctypeDeclHandler)(void *userData);
1671</pre>
1672<p>Set a handler that is called at the end of a DOCTYPE declaration,
1673after parsing any external subset.</p>
1674</div>
1675
1676<div class="handler">
1677<pre class="setter" id="XML_SetDoctypeDeclHandler">
1678void XMLCALL
1679XML_SetDoctypeDeclHandler(XML_Parser p,
1680			  XML_StartDoctypeDeclHandler start,
1681			  XML_EndDoctypeDeclHandler end);
1682</pre>
1683<p>Set both doctype handlers with one call.</p>
1684</div>
1685
1686<div class="handler">
1687<pre class="setter" id="XML_SetElementDeclHandler">
1688void XMLCALL
1689XML_SetElementDeclHandler(XML_Parser p,
1690			  XML_ElementDeclHandler eldecl);
1691</pre>
1692<pre class="signature">
1693typedef void
1694(XMLCALL *XML_ElementDeclHandler)(void *userData,
1695                                  const XML_Char *name,
1696                                  XML_Content *model);
1697</pre>
1698<pre class="signature">
1699enum XML_Content_Type {
1700  XML_CTYPE_EMPTY = 1,
1701  XML_CTYPE_ANY,
1702  XML_CTYPE_MIXED,
1703  XML_CTYPE_NAME,
1704  XML_CTYPE_CHOICE,
1705  XML_CTYPE_SEQ
1706};
1707
1708enum XML_Content_Quant {
1709  XML_CQUANT_NONE,
1710  XML_CQUANT_OPT,
1711  XML_CQUANT_REP,
1712  XML_CQUANT_PLUS
1713};
1714
1715typedef struct XML_cp XML_Content;
1716
1717struct XML_cp {
1718  enum XML_Content_Type		type;
1719  enum XML_Content_Quant	quant;
1720  const XML_Char *		name;
1721  unsigned int			numchildren;
1722  XML_Content *			children;
1723};
1724</pre>
1725<p>Sets a handler for element declarations in a DTD. The handler gets
1726called with the name of the element in the declaration and a pointer
1727to a structure that contains the element model. It is the
1728application's responsibility to free this data structure using
1729<code><a href="#XML_FreeContentModel"
1730>XML_FreeContentModel</a></code>.</p>
1731
1732<p>The <code>model</code> argument is the root of a tree of
1733<code>XML_Content</code> nodes. If <code>type</code> equals
1734<code>XML_CTYPE_EMPTY</code> or <code>XML_CTYPE_ANY</code>, then
1735<code>quant</code> will be <code>XML_CQUANT_NONE</code>, and the other
1736fields will be zero or NULL.  If <code>type</code> is
1737<code>XML_CTYPE_MIXED</code>, then <code>quant</code> will be
1738<code>XML_CQUANT_NONE</code> or <code>XML_CQUANT_REP</code> and
1739<code>numchildren</code> will contain the number of elements that are
1740allowed to be mixed in and <code>children</code> points to an array of
1741<code>XML_Content</code> structures that will all have type
1742XML_CTYPE_NAME with no quantification.  Only the root node can be type
1743<code>XML_CTYPE_EMPTY</code>, <code>XML_CTYPE_ANY</code>, or
1744<code>XML_CTYPE_MIXED</code>.</p>
1745
1746<p>For type <code>XML_CTYPE_NAME</code>, the <code>name</code> field
1747points to the name and the <code>numchildren</code> and
1748<code>children</code> fields will be zero and NULL. The
1749<code>quant</code> field will indicate any quantifiers placed on the
1750name.</p>
1751
1752<p>Types <code>XML_CTYPE_CHOICE</code> and <code>XML_CTYPE_SEQ</code>
1753indicate a choice or sequence respectively. The
1754<code>numchildren</code> field indicates how many nodes in the choice
1755or sequence and <code>children</code> points to the nodes.</p>
1756</div>
1757
1758<div class="handler">
1759<pre class="setter" id="XML_SetAttlistDeclHandler">
1760void XMLCALL
1761XML_SetAttlistDeclHandler(XML_Parser p,
1762                          XML_AttlistDeclHandler attdecl);
1763</pre>
1764<pre class="signature">
1765typedef void
1766(XMLCALL *XML_AttlistDeclHandler)(void           *userData,
1767                                  const XML_Char *elname,
1768                                  const XML_Char *attname,
1769                                  const XML_Char *att_type,
1770                                  const XML_Char *dflt,
1771                                  int            isrequired);
1772</pre>
1773<p>Set a handler for attlist declarations in the DTD. This handler is
1774called for <em>each</em> attribute. So a single attlist declaration
1775with multiple attributes declared will generate multiple calls to this
1776handler. The <code>elname</code> parameter returns the name of the
1777element for which the attribute is being declared. The attribute name
1778is in the <code>attname</code> parameter. The attribute type is in the
1779<code>att_type</code> parameter.  It is the string representing the
1780type in the declaration with whitespace removed.</p>
1781
1782<p>The <code>dflt</code> parameter holds the default value. It will be
1783NULL in the case of "#IMPLIED" or "#REQUIRED" attributes. You can
1784distinguish these two cases by checking the <code>isrequired</code>
1785parameter, which will be true in the case of "#REQUIRED" attributes.
1786Attributes which are "#FIXED" will have also have a true
1787<code>isrequired</code>, but they will have the non-NULL fixed value
1788in the <code>dflt</code> parameter.</p>
1789</div>
1790
1791<div class="handler">
1792<pre class="setter" id="XML_SetEntityDeclHandler">
1793void XMLCALL
1794XML_SetEntityDeclHandler(XML_Parser p,
1795			 XML_EntityDeclHandler handler);
1796</pre>
1797<pre class="signature">
1798typedef void
1799(XMLCALL *XML_EntityDeclHandler)(void           *userData,
1800                                 const XML_Char *entityName,
1801                                 int            is_parameter_entity,
1802                                 const XML_Char *value,
1803                                 int            value_length,
1804                                 const XML_Char *base,
1805                                 const XML_Char *systemId,
1806                                 const XML_Char *publicId,
1807                                 const XML_Char *notationName);
1808</pre>
1809<p>Sets a handler that will be called for all entity declarations.
1810The <code>is_parameter_entity</code> argument will be non-zero in the
1811case of parameter entities and zero otherwise.</p>
1812
1813<p>For internal entities (<code>&lt;!ENTITY foo "bar"&gt;</code>),
1814<code>value</code> will be non-NULL and <code>systemId</code>,
1815<code>publicId</code>, and <code>notationName</code> will all be NULL.
1816The value string is <em>not</em> NULL terminated; the length is
1817provided in the <code>value_length</code> parameter. Do not use
1818<code>value_length</code> to test for internal entities, since it is
1819legal to have zero-length values. Instead check for whether or not
1820<code>value</code> is NULL.</p> <p>The <code>notationName</code>
1821argument will have a non-NULL value only for unparsed entity
1822declarations.</p>
1823</div>
1824
1825<div class="handler">
1826<pre class="setter" id="XML_SetUnparsedEntityDeclHandler">
1827void XMLCALL
1828XML_SetUnparsedEntityDeclHandler(XML_Parser p,
1829                                 XML_UnparsedEntityDeclHandler h)
1830</pre>
1831<pre class="signature">
1832typedef void
1833(XMLCALL *XML_UnparsedEntityDeclHandler)(void *userData,
1834                                         const XML_Char *entityName,
1835                                         const XML_Char *base,
1836                                         const XML_Char *systemId,
1837                                         const XML_Char *publicId,
1838                                         const XML_Char *notationName);
1839</pre>
1840<p>Set a handler that receives declarations of unparsed entities. These
1841are entity declarations that have a notation (NDATA) field:</p>
1842
1843<div id="eg"><pre>
1844&lt;!ENTITY logo SYSTEM "images/logo.gif" NDATA gif&gt;
1845</pre></div>
1846<p>This handler is obsolete and is provided for backwards
1847compatibility.  Use instead <a href= "#XML_SetEntityDeclHandler"
1848>XML_SetEntityDeclHandler</a>.</p>
1849</div>
1850
1851<div class="handler">
1852<pre class="setter" id="XML_SetNotationDeclHandler">
1853void XMLCALL
1854XML_SetNotationDeclHandler(XML_Parser p,
1855                           XML_NotationDeclHandler h)
1856</pre>
1857<pre class="signature">
1858typedef void
1859(XMLCALL *XML_NotationDeclHandler)(void *userData,
1860                                   const XML_Char *notationName,
1861                                   const XML_Char *base,
1862                                   const XML_Char *systemId,
1863                                   const XML_Char *publicId);
1864</pre>
1865<p>Set a handler that receives notation declarations.</p>
1866</div>
1867
1868<div class="handler">
1869<pre class="setter" id="XML_SetNotStandaloneHandler">
1870void XMLCALL
1871XML_SetNotStandaloneHandler(XML_Parser p,
1872                            XML_NotStandaloneHandler h)
1873</pre>
1874<pre class="signature">
1875typedef int
1876(XMLCALL *XML_NotStandaloneHandler)(void *userData);
1877</pre>
1878<p>Set a handler that is called if the document is not "standalone".
1879This happens when there is an external subset or a reference to a
1880parameter entity, but does not have standalone set to "yes" in an XML
1881declaration.  If this handler returns <code>XML_STATUS_ERROR</code>,
1882then the parser will throw an <code>XML_ERROR_NOT_STANDALONE</code>
1883error.</p>
1884</div>
1885
1886<h3><a name="position">Parse position and error reporting functions</a></h3>
1887
1888<p>These are the functions you'll want to call when the parse
1889functions return <code>XML_STATUS_ERROR</code> (a parse error has
1890occurred), although the position reporting functions are useful outside
1891of errors. The position reported is the byte position (in the original
1892document or entity encoding) of the first of the sequence of
1893characters that generated the current event (or the error that caused
1894the parse functions to return <code>XML_STATUS_ERROR</code>.)  The
1895exceptions are callbacks trigged by declarations in the document
1896prologue, in which case they exact position reported is somewhere in the
1897relevant markup, but not necessarily as meaningful as for other
1898events.</p>
1899
1900<p>The position reporting functions are accurate only outside of the
1901DTD.  In other words, they usually return bogus information when
1902called from within a DTD declaration handler.</p>
1903
1904<pre class="fcndec" id="XML_GetErrorCode">
1905enum XML_Error XMLCALL
1906XML_GetErrorCode(XML_Parser p);
1907</pre>
1908<div class="fcndef">
1909Return what type of error has occurred.
1910</div>
1911
1912<pre class="fcndec" id="XML_ErrorString">
1913const XML_LChar * XMLCALL
1914XML_ErrorString(enum XML_Error code);
1915</pre>
1916<div class="fcndef">
1917Return a string describing the error corresponding to code.
1918The code should be one of the enums that can be returned from
1919<code><a href= "#XML_GetErrorCode" >XML_GetErrorCode</a></code>.
1920</div>
1921
1922<pre class="fcndec" id="XML_GetCurrentByteIndex">
1923XML_Index XMLCALL
1924XML_GetCurrentByteIndex(XML_Parser p);
1925</pre>
1926<div class="fcndef">
1927Return the byte offset of the position.  This always corresponds to
1928the values returned by <code><a href= "#XML_GetCurrentLineNumber"
1929>XML_GetCurrentLineNumber</a></code> and <code><a href=
1930"#XML_GetCurrentColumnNumber" >XML_GetCurrentColumnNumber</a></code>.
1931</div>
1932
1933<pre class="fcndec" id="XML_GetCurrentLineNumber">
1934XML_Size XMLCALL
1935XML_GetCurrentLineNumber(XML_Parser p);
1936</pre>
1937<div class="fcndef">
1938Return the line number of the position.  The first line is reported as
1939<code>1</code>.
1940</div>
1941
1942<pre class="fcndec" id="XML_GetCurrentColumnNumber">
1943XML_Size XMLCALL
1944XML_GetCurrentColumnNumber(XML_Parser p);
1945</pre>
1946<div class="fcndef">
1947Return the offset, from the beginning of the current line, of
1948the position.
1949</div>
1950
1951<pre class="fcndec" id="XML_GetCurrentByteCount">
1952int XMLCALL
1953XML_GetCurrentByteCount(XML_Parser p);
1954</pre>
1955<div class="fcndef">
1956Return the number of bytes in the current event. Returns
1957<code>0</code> if the event is inside a reference to an internal
1958entity and for the end-tag event for empty element tags (the later can
1959be used to distinguish empty-element tags from empty elements using
1960separate start and end tags).
1961</div>
1962
1963<pre class="fcndec" id="XML_GetInputContext">
1964const char * XMLCALL
1965XML_GetInputContext(XML_Parser p,
1966                    int *offset,
1967                    int *size);
1968</pre>
1969<div class="fcndef">
1970
1971<p>Returns the parser's input buffer, sets the integer pointed at by
1972<code>offset</code> to the offset within this buffer of the current
1973parse position, and set the integer pointed at by <code>size</code> to
1974the size of the returned buffer.</p>
1975
1976<p>This should only be called from within a handler during an active
1977parse and the returned buffer should only be referred to from within
1978the handler that made the call. This input buffer contains the
1979untranslated bytes of the input.</p>
1980
1981<p>Only a limited amount of context is kept, so if the event
1982triggering a call spans over a very large amount of input, the actual
1983parse position may be before the beginning of the buffer.</p>
1984
1985<p>If <code>XML_CONTEXT_BYTES</code> is not defined, this will always
1986return NULL.</p>
1987</div>
1988
1989<h3><a name="miscellaneous">Miscellaneous functions</a></h3>
1990
1991<p>The functions in this section either obtain state information from
1992the parser or can be used to dynamicly set parser options.</p>
1993
1994<pre class="fcndec" id="XML_SetUserData">
1995void XMLCALL
1996XML_SetUserData(XML_Parser p,
1997                void *userData);
1998</pre>
1999<div class="fcndef">
2000This sets the user data pointer that gets passed to handlers.  It
2001overwrites any previous value for this pointer. Note that the
2002application is responsible for freeing the memory associated with
2003<code>userData</code> when it is finished with the parser. So if you
2004call this when there's already a pointer there, and you haven't freed
2005the memory associated with it, then you've probably just leaked
2006memory.
2007</div>
2008
2009<pre class="fcndec" id="XML_GetUserData">
2010void * XMLCALL
2011XML_GetUserData(XML_Parser p);
2012</pre>
2013<div class="fcndef">
2014This returns the user data pointer that gets passed to handlers.
2015It is actually implemented as a macro.
2016</div>
2017
2018<pre class="fcndec" id="XML_UseParserAsHandlerArg">
2019void XMLCALL
2020XML_UseParserAsHandlerArg(XML_Parser p);
2021</pre>
2022<div class="fcndef">
2023After this is called, handlers receive the parser in their
2024<code>userData</code> arguments.  The user data can still be obtained
2025using the <code><a href= "#XML_GetUserData"
2026>XML_GetUserData</a></code> function.
2027</div>
2028
2029<pre class="fcndec" id="XML_SetBase">
2030enum XML_Status XMLCALL
2031XML_SetBase(XML_Parser p,
2032            const XML_Char *base);
2033</pre>
2034<div class="fcndef">
2035Set the base to be used for resolving relative URIs in system
2036identifiers.  The return value is <code>XML_STATUS_ERROR</code> if
2037there's no memory to store base, otherwise it's
2038<code>XML_STATUS_OK</code>.
2039</div>
2040
2041<pre class="fcndec" id="XML_GetBase">
2042const XML_Char * XMLCALL
2043XML_GetBase(XML_Parser p);
2044</pre>
2045<div class="fcndef">
2046Return the base for resolving relative URIs.
2047</div>
2048
2049<pre class="fcndec" id="XML_GetSpecifiedAttributeCount">
2050int XMLCALL
2051XML_GetSpecifiedAttributeCount(XML_Parser p);
2052</pre>
2053<div class="fcndef">
2054When attributes are reported to the start handler in the atts vector,
2055attributes that were explicitly set in the element occur before any
2056attributes that receive their value from default information in an
2057ATTLIST declaration. This function returns the number of attributes
2058that were explicitly set times two, thus giving the offset in the
2059<code>atts</code> array passed to the start tag handler of the first
2060attribute set due to defaults. It supplies information for the last
2061call to a start handler. If called inside a start handler, then that
2062means the current call.
2063</div>
2064
2065<pre class="fcndec" id="XML_GetIdAttributeIndex">
2066int XMLCALL
2067XML_GetIdAttributeIndex(XML_Parser p);
2068</pre>
2069<div class="fcndef">
2070Returns the index of the ID attribute passed in the atts array in the
2071last call to <code><a href= "#XML_StartElementHandler"
2072>XML_StartElementHandler</a></code>, or -1 if there is no ID
2073attribute. If called inside a start handler, then that means the
2074current call.
2075</div>
2076
2077<pre class="fcndec" id="XML_SetEncoding">
2078enum XML_Status XMLCALL
2079XML_SetEncoding(XML_Parser p,
2080                const XML_Char *encoding);
2081</pre>
2082<div class="fcndef">
2083Set the encoding to be used by the parser. It is equivalent to
2084passing a non-null encoding argument to the parser creation functions.
2085It must not be called after <code><a href= "#XML_Parse"
2086>XML_Parse</a></code> or <code><a href= "#XML_ParseBuffer"
2087>XML_ParseBuffer</a></code> have been called on the given parser.
2088Returns <code>XML_STATUS_OK</code> on success or
2089<code>XML_STATUS_ERROR</code> on error.
2090</div>
2091
2092<pre class="fcndec" id="XML_SetParamEntityParsing">
2093int XMLCALL
2094XML_SetParamEntityParsing(XML_Parser p,
2095                          enum XML_ParamEntityParsing code);
2096</pre>
2097<div class="fcndef">
2098This enables parsing of parameter entities, including the external
2099parameter entity that is the external DTD subset, according to
2100<code>code</code>.
2101The choices for <code>code</code> are:
2102<ul>
2103<li><code>XML_PARAM_ENTITY_PARSING_NEVER</code></li>
2104<li><code>XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE</code></li>
2105<li><code>XML_PARAM_ENTITY_PARSING_ALWAYS</code></li>
2106</ul>
2107</div>
2108
2109<pre class="fcndec" id="XML_UseForeignDTD">
2110enum XML_Error XMLCALL
2111XML_UseForeignDTD(XML_Parser parser, XML_Bool useDTD);
2112</pre>
2113<div class="fcndef">
2114<p>This function allows an application to provide an external subset
2115for the document type declaration for documents which do not specify
2116an external subset of their own.  For documents which specify an
2117external subset in their DOCTYPE declaration, the application-provided
2118subset will be ignored.  If the document does not contain a DOCTYPE
2119declaration at all and <code>useDTD</code> is true, the
2120application-provided subset will be parsed, but the
2121<code>startDoctypeDeclHandler</code> and
2122<code>endDoctypeDeclHandler</code> functions, if set, will not be
2123called.  The setting of parameter entity parsing, controlled using
2124<code><a href= "#XML_SetParamEntityParsing"
2125>XML_SetParamEntityParsing</a></code>, will be honored.</p>
2126
2127<p>The application-provided external subset is read by calling the
2128external entity reference handler set via <code><a href=
2129"#XML_SetExternalEntityRefHandler"
2130>XML_SetExternalEntityRefHandler</a></code> with both
2131<code>publicId</code> and <code>systemId</code> set to NULL.</p>
2132
2133<p>If this function is called after parsing has begun, it returns
2134<code>XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING</code> and ignores
2135<code>useDTD</code>.  If called when Expat has been compiled without
2136DTD support, it returns
2137<code>XML_ERROR_FEATURE_REQUIRES_XML_DTD</code>.  Otherwise, it
2138returns <code>XML_ERROR_NONE</code>.</p>
2139
2140<p><b>Note:</b> For the purpose of checking WFC: Entity Declared, passing
2141<code>useDTD == XML_TRUE</code> will make the parser behave as if
2142the document had a DTD with an external subset. This holds true even if
2143the external entity reference handler returns without action.</p>
2144</div>
2145
2146<pre class="fcndec" id="XML_SetReturnNSTriplet">
2147void XMLCALL
2148XML_SetReturnNSTriplet(XML_Parser parser,
2149                       int        do_nst);
2150</pre>
2151<div class="fcndef">
2152<p>
2153This function only has an effect when using a parser created with
2154<code><a href= "#XML_ParserCreateNS" >XML_ParserCreateNS</a></code>,
2155i.e. when namespace processing is in effect. The <code>do_nst</code>
2156sets whether or not prefixes are returned with names qualified with a
2157namespace prefix. If this function is called with <code>do_nst</code>
2158non-zero, then afterwards namespace qualified names (that is qualified
2159with a prefix as opposed to belonging to a default namespace) are
2160returned as a triplet with the three parts separated by the namespace
2161separator specified when the parser was created.  The order of
2162returned parts is URI, local name, and prefix.</p> <p>If
2163<code>do_nst</code> is zero, then namespaces are reported in the
2164default manner, URI then local_name separated by the namespace
2165separator.</p>
2166</div>
2167
2168<pre class="fcndec" id="XML_DefaultCurrent">
2169void XMLCALL
2170XML_DefaultCurrent(XML_Parser parser);
2171</pre>
2172<div class="fcndef">
2173This can be called within a handler for a start element, end element,
2174processing instruction or character data.  It causes the corresponding
2175markup to be passed to the default handler set by <code><a
2176href="#XML_SetDefaultHandler" >XML_SetDefaultHandler</a></code> or
2177<code><a href="#XML_SetDefaultHandlerExpand"
2178>XML_SetDefaultHandlerExpand</a></code>.  It does nothing if there is
2179not a default handler.
2180</div>
2181
2182<pre class="fcndec" id="XML_ExpatVersion">
2183XML_LChar * XMLCALL
2184XML_ExpatVersion();
2185</pre>
2186<div class="fcndef">
2187Return the library version as a string (e.g. <code>"expat_1.95.1"</code>).
2188</div>
2189
2190<pre class="fcndec" id="XML_ExpatVersionInfo">
2191struct XML_Expat_Version XMLCALL
2192XML_ExpatVersionInfo();
2193</pre>
2194<pre class="signature">
2195typedef struct {
2196  int major;
2197  int minor;
2198  int micro;
2199} XML_Expat_Version;
2200</pre>
2201<div class="fcndef">
2202Return the library version information as a structure.
2203Some macros are also defined that support compile-time tests of the
2204library version:
2205<ul>
2206<li><code>XML_MAJOR_VERSION</code></li>
2207<li><code>XML_MINOR_VERSION</code></li>
2208<li><code>XML_MICRO_VERSION</code></li>
2209</ul>
2210Testing these constants is currently the best way to determine if
2211particular parts of the Expat API are available.
2212</div>
2213
2214<pre class="fcndec" id="XML_GetFeatureList">
2215const XML_Feature * XMLCALL
2216XML_GetFeatureList();
2217</pre>
2218<pre class="signature">
2219enum XML_FeatureEnum {
2220  XML_FEATURE_END = 0,
2221  XML_FEATURE_UNICODE,
2222  XML_FEATURE_UNICODE_WCHAR_T,
2223  XML_FEATURE_DTD,
2224  XML_FEATURE_CONTEXT_BYTES,
2225  XML_FEATURE_MIN_SIZE,
2226  XML_FEATURE_SIZEOF_XML_CHAR,
2227  XML_FEATURE_SIZEOF_XML_LCHAR,
2228  XML_FEATURE_NS,
2229  XML_FEATURE_LARGE_SIZE
2230};
2231
2232typedef struct {
2233  enum XML_FeatureEnum  feature;
2234  XML_LChar            *name;
2235  long int              value;
2236} XML_Feature;
2237</pre>
2238<div class="fcndef">
2239<p>Returns a list of "feature" records, providing details on how
2240Expat was configured at compile time.  Most applications should not
2241need to worry about this, but this information is otherwise not
2242available from Expat.  This function allows code that does need to
2243check these features to do so at runtime.</p>
2244
2245<p>The return value is an array of <code>XML_Feature</code>,
2246terminated by a record with a <code>feature</code> of
2247<code>XML_FEATURE_END</code> and <code>name</code> of NULL,
2248identifying the feature-test macros Expat was compiled with.  Since an
2249application that requires this kind of information needs to determine
2250the type of character the <code>name</code> points to, records for the
2251<code>XML_FEATURE_SIZEOF_XML_CHAR</code> and
2252<code>XML_FEATURE_SIZEOF_XML_LCHAR</code> will be located at the
2253beginning of the list, followed by <code>XML_FEATURE_UNICODE</code>
2254and <code>XML_FEATURE_UNICODE_WCHAR_T</code>, if they are present at
2255all.</p>
2256
2257<p>Some features have an associated value.  If there isn't an
2258associated value, the <code>value</code> field is set to 0.  At this
2259time, the following features have been defined to have values:</p>
2260
2261<dl>
2262  <dt><code>XML_FEATURE_SIZEOF_XML_CHAR</code></dt>
2263  <dd>The number of bytes occupied by one <code>XML_Char</code>
2264  character.</dd>
2265  <dt><code>XML_FEATURE_SIZEOF_XML_LCHAR</code></dt>
2266  <dd>The number of bytes occupied by one <code>XML_LChar</code>
2267  character.</dd>
2268  <dt><code>XML_FEATURE_CONTEXT_BYTES</code></dt>
2269  <dd>The maximum number of characters of context which can be
2270  reported by <code><a href= "#XML_GetInputContext"
2271  >XML_GetInputContext</a></code>.</dd>
2272</dl>
2273</div>
2274
2275<pre class="fcndec" id="XML_FreeContentModel">
2276void XMLCALL
2277XML_FreeContentModel(XML_Parser parser, XML_Content *model);
2278</pre>
2279<div class="fcndef">
2280Function to deallocate the <code>model</code> argument passed to the
2281<code>XML_ElementDeclHandler</code> callback set using <code><a
2282href="#XML_SetElementDeclHandler" >XML_ElementDeclHandler</a></code>.
2283This function should not be used for any other purpose.
2284</div>
2285
2286<p>The following functions allow external code to share the memory
2287allocator an <code>XML_Parser</code> has been configured to use.  This
2288is especially useful for third-party libraries that interact with a
2289parser object created by application code, or heavily layered
2290applications.  This can be essential when using dynamically loaded
2291libraries which use different C standard libraries (this can happen on
2292Windows, at least).</p>
2293
2294<pre class="fcndec" id="XML_MemMalloc">
2295void * XMLCALL
2296XML_MemMalloc(XML_Parser parser, size_t size);
2297</pre>
2298<div class="fcndef">
2299Allocate <code>size</code> bytes of memory using the allocator the
2300<code>parser</code> object has been configured to use.  Returns a
2301pointer to the memory or NULL on failure.  Memory allocated in this
2302way must be freed using <code><a href="#XML_MemFree"
2303>XML_MemFree</a></code>.
2304</div>
2305
2306<pre class="fcndec" id="XML_MemRealloc">
2307void * XMLCALL
2308XML_MemRealloc(XML_Parser parser, void *ptr, size_t size);
2309</pre>
2310<div class="fcndef">
2311Allocate <code>size</code> bytes of memory using the allocator the
2312<code>parser</code> object has been configured to use.
2313<code>ptr</code> must point to a block of memory allocated by <code><a
2314href="#XML_MemMalloc" >XML_MemMalloc</a></code> or
2315<code>XML_MemRealloc</code>, or be NULL.  This function tries to
2316expand the block pointed to by <code>ptr</code> if possible.  Returns
2317a pointer to the memory or NULL on failure.  On success, the original
2318block has either been expanded or freed.  On failure, the original
2319block has not been freed; the caller is responsible for freeing the
2320original block.  Memory allocated in this way must be freed using
2321<code><a href="#XML_MemFree"
2322>XML_MemFree</a></code>.
2323</div>
2324
2325<pre class="fcndec" id="XML_MemFree">
2326void XMLCALL
2327XML_MemFree(XML_Parser parser, void *ptr);
2328</pre>
2329<div class="fcndef">
2330Free a block of memory pointed to by <code>ptr</code>.  The block must
2331have been allocated by <code><a href="#XML_MemMalloc"
2332>XML_MemMalloc</a></code> or <code>XML_MemRealloc</code>, or be NULL.
2333</div>
2334
2335<hr />
2336<p><a href="http://validator.w3.org/check/referer"><img
2337        src="valid-xhtml10.png" alt="Valid XHTML 1.0!"
2338        height="31" width="88" class="noborder" /></a></p>
2339</div>
2340</body>
2341</html>
2342