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libxml,在UNIX/LINUX下非常重要的一个库,为XML相关应用提供方便.目前上载的是最新版本,若要取得最新版本,请参考里面的readme.

      respectively.</li>
      <li>In order to use this "private" library, you should first add it
      to the beginning of your default PATH (so that your own private
      program files such as xmllint will be used instead of the normal
      system ones).  To do this, the Bash command would be
      <p><code>export PATH=/home/user/myxml/xmlinst/bin:$PATH</code></p></li>
      <li>Now suppose you have a program <code>test1.c</code> that you would
      like to compile with your "private" library.  Simply compile it
      using the command <p><code>gcc `xml2-config --cflags --libs` -o test
      test.c</code></p>  Note that, because your PATH has been set with <code>
      /home/user/myxml/xmlinst/bin</code> at the beginning, the
      xml2-config program which you just installed will be used instead of
      the system default one, and this will <em>automatically</em> get the
      correct libraries linked with your program.</li></ul></li><p></p>
  <li><em>xmlDocDump() generates output on one line.</em>
    <p>Libxml2 will not <strong>invent</strong> spaces in the content of a
    document since <strong>all spaces in the content of a document are
    significant</strong>. If you build a tree from the API and want
    indentation:</p>
    <ol><li>the correct way is to generate those yourself too.</li>
      <li>the dangerous way is to ask libxml2 to add those blanks to your
        content <strong>modifying the content of your document in the
        process</strong>. The result may not be what you expect. There is
        <strong>NO</strong> way to guarantee that such a modification won't
        affect other parts of the content of your document. See <a href="http://xmlsoft.org/html/libxml-parser.html#xmlKeepBlanksDefault">xmlKeepBlanksDefault
        ()</a> and <a href="http://xmlsoft.org/html/libxml-tree.html#xmlSaveFormatFile">xmlSaveFormatFile
        ()</a></li>
    </ol></li>
  <li>Extra nodes in the document:
    <p><em>For a XML file as below:</em></p>
    <pre>&lt;?xml version="1.0"?&gt;
&lt;PLAN xmlns="http://www.argus.ca/autotest/1.0/"&gt;
&lt;NODE CommFlag="0"/&gt;
&lt;NODE CommFlag="1"/&gt;
&lt;/PLAN&gt;</pre>
    <p><em>after parsing it with the function
    pxmlDoc=xmlParseFile(...);</em></p>
    <p><em>I want to the get the content of the first node (node with the
    CommFlag="0")</em></p>
    <p><em>so I did it as following;</em></p>
    <pre>xmlNodePtr pnode;
pnode=pxmlDoc-&gt;children-&gt;children;</pre>
    <p><em>but it does not work. If I change it to</em></p>
    <pre>pnode=pxmlDoc-&gt;children-&gt;children-&gt;next;</pre>
    <p><em>then it works.  Can someone explain it to me.</em></p>
    <p></p>
    <p>In XML all characters in the content of the document are significant
    <strong>including blanks and formatting line breaks</strong>.</p>
    <p>The extra nodes you are wondering about are just that, text nodes with
    the formatting spaces which are part of the document but that people tend
    to forget. There is a function <a href="http://xmlsoft.org/html/libxml-parser.html">xmlKeepBlanksDefault
    ()</a>  to remove those at parse time, but that's an heuristic, and its
    use should be limited to cases where you are certain there is no
    mixed-content in the document.</p>
  </li>
  <li><em>I get compilation errors of existing code like when accessing
    <strong>root</strong> or <strong>child fields</strong> of nodes.</em>
    <p>You are compiling code developed for libxml version 1 and using a
    libxml2 development environment. Either switch back to libxml v1 devel or
    even better fix the code to compile with libxml2 (or both) by <a href="upgrade.html">following the instructions</a>.</p>
  </li>
  <li><em>I get compilation errors about non existing
    <strong>xmlRootNode</strong> or <strong>xmlChildrenNode</strong>
    fields.</em>
    <p>The source code you are using has been <a href="upgrade.html">upgraded</a> to be able to compile with both libxml
    and libxml2, but you need to install a more recent version:
    libxml(-devel) &gt;= 1.8.8 or libxml2(-devel) &gt;= 2.1.0</p>
  </li>
  <li><em>XPath implementation looks seriously broken</em>
    <p>XPath implementation prior to 2.3.0 was really incomplete. Upgrade to
    a recent version, there are no known bugs in the current version.</p>
  </li>
  <li><em>The example provided in the web page does not compile.</em>
    <p>It's hard to maintain the documentation in sync with the code
    &lt;grin/&gt; ...</p>
    <p>Check the previous points 1/ and 2/ raised before, and please send
    patches.</p>
  </li>
  <li><em>Where can I get more examples and information than provided on the
    web page?</em>
    <p>Ideally a libxml2 book would be nice. I have no such plan ... But you
    can:</p>
    <ul><li>check more deeply the <a href="html/libxml-lib.html">existing
        generated doc</a></li>
      <li>have a look at <a href="examples/index.html">the set of
        examples</a>.</li>
      <li>look for examples of use for libxml2 function using the Gnome code.
        For example the following will query the full Gnome CVS base for the
        use of the <strong>xmlAddChild()</strong> function:
        <p><a href="http://cvs.gnome.org/lxr/search?string=xmlAddChild">http://cvs.gnome.org/lxr/search?string=xmlAddChild</a></p>
        <p>This may be slow, a large hardware donation to the gnome project
        could cure this :-)</p>
      </li>
      <li><a href="http://cvs.gnome.org/bonsai/rview.cgi?cvsroot=/cvs/gnome&amp;dir=gnome-xml">Browse
        the libxml2 source</a> , I try to write code as clean and documented
        as possible, so looking at it may be helpful. In particular the code
        of xmllint.c and of the various testXXX.c test programs should
        provide good examples of how to do things with the library.</li>
    </ul></li>
  <li>What about C++ ?
    <p>libxml2 is written in pure C in order to allow easy reuse on a number
    of platforms, including embedded systems. I don't intend to convert to
    C++.</p>
    <p>There is however a C++ wrapper which may fulfill your needs:</p>
    <ul><li>by Ari Johnson &lt;[e-mail]&gt;:
        <p>Website: <a href="http://libxmlplusplus.sourceforge.net/">http://libxmlplusplus.sourceforge.net/</a></p>
        <p>Download: <a href="http://sourceforge.net/project/showfiles.php?group_id=12999">http://sourceforge.net/project/showfiles.php?group_id=12999</a></p>
      </li>
      <!-- Website is currently unavailable as of 2003-08-02
      <li>by Peter Jones &lt;[e-mail]&gt;
      <p>Website: <a
      href="http://pmade.org/pjones/software/xmlwrapp/">http://pmade.org/pjones/software/xmlwrapp/</a></p>
      </li>
      -->
    </ul></li>
  <li>How to validate a document a posteriori ?
    <p>It is possible to validate documents which had not been validated at
    initial parsing time or documents which have been built from scratch
    using the API. Use the <a href="http://xmlsoft.org/html/libxml-valid.html#xmlValidateDtd">xmlValidateDtd()</a>
    function. It is also possible to simply add a DTD to an existing
    document:</p>
    <pre>xmlDocPtr doc; /* your existing document */
xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */

        dtd-&gt;name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */

        doc-&gt;intSubset = dtd;
        if (doc-&gt;children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
        else xmlAddPrevSibling(doc-&gt;children, (xmlNodePtr)dtd);
          </pre>
  </li>
  <li>So what is this funky "xmlChar" used all the time?
    <p>It is a null terminated sequence of utf-8 characters. And only utf-8!
    You need to convert strings encoded in different ways to utf-8 before
    passing them to the API.  This can be accomplished with the iconv library
    for instance.</p>
  </li>
  <li>etc ...</li>
</ol><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>