preparing release of 2.6.25 Daniel
* configure.ini NEWS doc//* libxml.spec.in : preparing release of 2.6.25
Daniel
diff --git a/doc/xmlmem.html b/doc/xmlmem.html
index 58c2987..547a7ed 100644
--- a/doc/xmlmem.html
+++ b/doc/xmlmem.html
@@ -12,91 +12,92 @@
<li><a href="#cleanup">Cleaning up after parsing</a></li>
<li><a href="#Debugging">Debugging routines</a></li>
<li><a href="#General4">General memory requirements</a></li>
-</ol><h3><a name="General3" id="General3">General overview</a></h3><p>The module <code><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>
-provides the interfaces to the libxml2 memory system:</p><ul><li>libxml2 does not use the libc memory allocator directly but xmlFree(),
- xmlMalloc() and xmlRealloc()</li>
- <li>those routines can be reallocated to a specific set of routine, by
- default the libc ones i.e. free(), malloc() and realloc()</li>
+</ol><h3><a name="General3" id="General3">General overview</a></h3><p>The module <code><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlmemory.h</a></code>provides
+the interfaces to the libxml2 memory system:</p><ul><li>libxml2 does not use the libc memory allocator directly but
+ xmlFree(),xmlMalloc() and xmlRealloc()</li>
+ <li>those routines can be reallocated to a specific set of routine,
+ bydefault the libc ones i.e. free(), malloc() and realloc()</li>
<li>the xmlmemory.c module includes a set of debugging routine</li>
-</ul><h3><a name="setting" id="setting">Setting libxml2 set of memory routines</a></h3><p>It is sometimes useful to not use the default memory allocator, either for
-debugging, analysis or to implement a specific behaviour on memory management
-(like on embedded systems). Two function calls are available to do so:</p><ul><li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet
- ()</a> which return the current set of functions in use by the parser</li>
- <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>
- which allow to set up a new set of memory allocation functions</li>
-</ul><p>Of course a call to xmlMemSetup() should probably be done before calling
-any other libxml2 routines (unless you are sure your allocations routines are
-compatibles).</p><h3><a name="cleanup" id="cleanup">Cleaning up after parsing</a></h3><p>Libxml2 is not stateless, there is a few set of memory structures needing
-allocation before the parser is fully functional (some encoding structures
-for example). This also mean that once parsing is finished there is a tiny
-amount of memory (a few hundred bytes) which can be recollected if you don't
-reuse the parser immediately:</p><ul><li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser
- ()</a> is a centralized routine to free the parsing states. Note that it
- won't deallocate any produced tree if any (use the xmlFreeDoc() and
- related routines for this).</li>
- <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser
- ()</a> is the dual routine allowing to preallocate the parsing state
- which can be useful for example to avoid initialization reentrancy
- problems when using libxml2 in multithreaded applications</li>
-</ul><p>Generally xmlCleanupParser() is safe, if needed the state will be rebuild
-at the next invocation of parser routines, but be careful of the consequences
-in multithreaded applications.</p><h3><a name="Debugging" id="Debugging">Debugging routines</a></h3><p>When configured using --with-mem-debug flag (off by default), libxml2 uses
-a set of memory allocation debugging routines keeping track of all allocated
-blocks and the location in the code where the routine was called. A couple of
-other debugging routines allow to dump the memory allocated infos to a file
-or call a specific routine when a given block number is allocated:</p><ul><li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a>
- <a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>
- and <a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>
- are the memory debugging replacement allocation routines</li>
- <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump
- ()</a> dumps all the informations about the allocated memory block lefts
- in the <code>.memdump</code> file</li>
-</ul><p>When developing libxml2 memory debug is enabled, the tests programs call
-xmlMemoryDump () and the "make test" regression tests will check for any
-memory leak during the full regression test sequence, this helps a lot
-ensuring that libxml2 does not leak memory and bullet proof memory
-allocations use (some libc implementations are known to be far too permissive
-resulting in major portability problems!).</p><p>If the .memdump reports a leak, it displays the allocation function and
-also tries to give some informations about the content and structure of the
-allocated blocks left. This is sufficient in most cases to find the culprit,
-but not always. Assuming the allocation problem is reproducible, it is
-possible to find more easily:</p><ol><li>write down the block number xxxx not allocated</li>
- <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the easiest
- when using GDB is to simply give the command
+</ul><h3><a name="setting" id="setting">Setting libxml2 set of memory routines</a></h3><p>It is sometimes useful to not use the default memory allocator, either
+fordebugging, analysis or to implement a specific behaviour on memory
+management(like on embedded systems). Two function calls are available to do
+so:</p><ul><li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemGet()</a>which
+ return the current set of functions in use by the parser</li>
+ <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemSetup()</a>which
+ allow to set up a new set of memory allocation functions</li>
+</ul><p>Of course a call to xmlMemSetup() should probably be done before
+callingany other libxml2 routines (unless you are sure your allocations
+routines arecompatibles).</p><h3><a name="cleanup" id="cleanup">Cleaning up after parsing</a></h3><p>Libxml2 is not stateless, there is a few set of memory structures
+needingallocation before the parser is fully functional (some encoding
+structuresfor example). This also mean that once parsing is finished there is
+a tinyamount of memory (a few hundred bytes) which can be recollected if you
+don'treuse the parser immediately:</p><ul><li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlCleanupParser()</a>is
+ a centralized routine to free the parsing states. Note that itwon't
+ deallocate any produced tree if any (use the xmlFreeDoc() andrelated
+ routines for this).</li>
+ <li><a href="http://xmlsoft.org/html/libxml-parser.html">xmlInitParser()</a>is
+ the dual routine allowing to preallocate the parsing statewhich can be
+ useful for example to avoid initialization reentrancyproblems when using
+ libxml2 in multithreaded applications</li>
+</ul><p>Generally xmlCleanupParser() is safe, if needed the state will be
+rebuildat the next invocation of parser routines, but be careful of the
+consequencesin multithreaded applications.</p><h3><a name="Debugging" id="Debugging">Debugging routines</a></h3><p>When configured using --with-mem-debug flag (off by default), libxml2
+usesa set of memory allocation debugging routines keeping track of all
+allocatedblocks and the location in the code where the routine was called. A
+couple ofother debugging routines allow to dump the memory allocated infos to
+a fileor call a specific routine when a given block number is allocated:</p><ul><li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMallocLoc()</a><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlReallocLoc()</a>and
+ <a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemStrdupLoc()</a>are
+ the memory debugging replacement allocation routines</li>
+ <li><a href="http://xmlsoft.org/html/libxml-xmlmemory.html">xmlMemoryDump()</a>dumps
+ all the informations about the allocated memory block leftsin the
+ <code>.memdump</code>file</li>
+</ul><p>When developing libxml2 memory debug is enabled, the tests programs
+callxmlMemoryDump () and the "make test" regression tests will check for
+anymemory leak during the full regression test sequence, this helps a
+lotensuring that libxml2 does not leak memory and bullet proof
+memoryallocations use (some libc implementations are known to be far too
+permissiveresulting in major portability problems!).</p><p>If the .memdump reports a leak, it displays the allocation function
+andalso tries to give some informations about the content and structure of
+theallocated blocks left. This is sufficient in most cases to find the
+culprit,but not always. Assuming the allocation problem is reproducible, it
+ispossible to find more easily:</p><ol><li>write down the block number xxxx not allocated</li>
+ <li>export the environment variable XML_MEM_BREAKPOINT=xxxx , the
+ easiestwhen using GDB is to simply give the command
<p><code>set environment XML_MEM_BREAKPOINT xxxx</code></p>
<p>before running the program.</p>
</li>
- <li>run the program under a debugger and set a breakpoint on
- xmlMallocBreakpoint() a specific function called when this precise block
- is allocated</li>
- <li>when the breakpoint is reached you can then do a fine analysis of the
- allocation an step to see the condition resulting in the missing
- deallocation.</li>
-</ol><p>I used to use a commercial tool to debug libxml2 memory problems but after
-noticing that it was not detecting memory leaks that simple mechanism was
-used and proved extremely efficient until now. Lately I have also used <a href="http://developer.kde.org/~sewardj/">valgrind</a> with quite some
-success, it is tied to the i386 architecture since it works by emulating the
-processor and instruction set, it is slow but extremely efficient, i.e. it
-spot memory usage errors in a very precise way.</p><h3><a name="General4" id="General4">General memory requirements</a></h3><p>How much libxml2 memory require ? It's hard to tell in average it depends
-of a number of things:</p><ul><li>the parser itself should work in a fixed amount of memory, except for
- information maintained about the stacks of names and entities locations.
- The I/O and encoding handlers will probably account for a few KBytes.
- This is true for both the XML and HTML parser (though the HTML parser
- need more state).</li>
- <li>If you are generating the DOM tree then memory requirements will grow
- nearly linear with the size of the data. In general for a balanced
- textual document the internal memory requirement is about 4 times the
- size of the UTF8 serialization of this document (example the XML-1.0
- recommendation is a bit more of 150KBytes and takes 650KBytes of main
- memory when parsed). Validation will add a amount of memory required for
- maintaining the external Dtd state which should be linear with the
- complexity of the content model defined by the Dtd</li>
- <li>If you need to work with fixed memory requirements or don't need the
- full DOM tree then using the <a href="xmlreader.html">xmlReader
- interface</a> is probably the best way to proceed, it still allows to
- validate or operate on subset of the tree if needed.</li>
- <li>If you don't care about the advanced features of libxml2 like
- validation, DOM, XPath or XPointer, don't use entities, need to work with
- fixed memory requirements, and try to get the fastest parsing possible
- then the SAX interface should be used, but it has known restrictions.</li>
+ <li>run the program under a debugger and set a breakpoint
+ onxmlMallocBreakpoint() a specific function called when this precise
+ blockis allocated</li>
+ <li>when the breakpoint is reached you can then do a fine analysis of
+ theallocation an step to see the condition resulting in the
+ missingdeallocation.</li>
+</ol><p>I used to use a commercial tool to debug libxml2 memory problems but
+afternoticing that it was not detecting memory leaks that simple mechanism
+wasused and proved extremely efficient until now. Lately I have also used <a href="http://developer.kde.org/~sewardj/">valgrind</a>with quite somesuccess,
+it is tied to the i386 architecture since it works by emulating theprocessor
+and instruction set, it is slow but extremely efficient, i.e. itspot memory
+usage errors in a very precise way.</p><h3><a name="General4" id="General4">General memory requirements</a></h3><p>How much libxml2 memory require ? It's hard to tell in average it
+dependsof a number of things:</p><ul><li>the parser itself should work in a fixed amount of memory, except
+ forinformation maintained about the stacks of names and entities
+ locations.The I/O and encoding handlers will probably account for a few
+ KBytes.This is true for both the XML and HTML parser (though the HTML
+ parserneed more state).</li>
+ <li>If you are generating the DOM tree then memory requirements will
+ grownearly linear with the size of the data. In general for a
+ balancedtextual document the internal memory requirement is about 4 times
+ thesize of the UTF8 serialization of this document (example the
+ XML-1.0recommendation is a bit more of 150KBytes and takes 650KBytes of
+ mainmemory when parsed). Validation will add a amount of memory required
+ formaintaining the external Dtd state which should be linear with
+ thecomplexity of the content model defined by the Dtd</li>
+ <li>If you need to work with fixed memory requirements or don't need
+ thefull DOM tree then using the <a href="xmlreader.html">xmlReaderinterface</a>is probably the best way to
+ proceed, it still allows tovalidate or operate on subset of the tree if
+ needed.</li>
+ <li>If you don't care about the advanced features of libxml2
+ likevalidation, DOM, XPath or XPointer, don't use entities, need to work
+ withfixed memory requirements, and try to get the fastest parsing
+ possiblethen the SAX interface should be used, but it has known
+ restrictions.</li>
</ul><p></p><p><a href="bugs.html">Daniel Veillard</a></p></td></tr></table></td></tr></table></td></tr></table></td></tr></table></td></tr></table></body></html>