|  | | | | Table of Contents: Licensing Terms for libxml
    libxml2 is released under the MITLicense;see
    the file Copyright in the distribution for the precisewordingCan I embed libxml2 in a proprietary application ?
    Yes. The MIT License allows you to keep proprietary the changesyoumade
    to libxml, but it would be graceful to send-back bug fixesandimprovements
    as patches for possible incorporation in themaindevelopment tree.
 Do
    NotUselibxml1, use libxml2Where can I get libxml?
    The original distribution comes from xmlsoft.orgor gnome.org Most Linux and BSD distributions include libxml, this is
    probablythesafer way for end-users to use libxml. David Doolin provides precompiled Windows versions at http://www.ce.berkeley.edu/~doolin/code/libxmlwin32/I see libxml and libxml2 releases, which one should I install ?
    If you are not constrained by backward compatibility
        issueswithexisting applications, install libxml2 onlyIf you are not doing development, you can safely
        installboth.Usually the packages libxmland libxml2arecompatible(this
        is not the case for development packages).If you are a developer and your system provides
        separatepackagingfor shared libraries and the development components,
        it ispossibleto install libxml and libxml2, and also libxml-develandlibxml2-develtoofor
        libxml2 >= 2.3.0If you are developing a new application, please
        developagainstlibxml2(-devel)
I can't install the libxml package, it conflicts with libxml0
    You probably have an old libxml0 package used to provide
    thesharedlibrary for libxml.so.0, you can probably safely remove it.
    Thelibxmlpackages provided on xmlsoft.orgprovidelibxml.so.0I can't install the libxml(2) RPM package due
    tofaileddependencies
    The most generic solution is to re-fetch the latest src.rpm
    ,andrebuild it locally with rpm --rebuild libxml(2)-xxx.src.rpm.
 If everything goes well it will generate two binary rpm
    packages(oneproviding the shared libs and xmllint, and the other one,
    the-develpackage, providing includes, static libraries and scripts needed
    tobuildapplications with libxml(2)) that you can install locally.
 What is the process to compile libxml2 ?
    As most UNIX libraries libxml2 follows the "standard": gunzip -c xxx.tar.gz | tar xvf -
 cd libxml-xxxx
 ./configure --help
 to see the options, then the compilation/installation proper ./configure [possible options]
 make
 make install
 At that point you may have to rerun ldconfig or a similar
    utilitytoupdate your list of installed shared libs.What other libraries are needed to compile/install libxml2 ?
    Libxml2 does not require any other library, the normal C ANSIAPIshould
    be sufficient (please report any violation to this rule youmayfind). However if found at configuration time libxml2 will detect and
    usethefollowing libs: libz:ahighly
        portable and available widely compression library.iconv: a powerful character encoding conversion library.
        Itisincluded by default in recent glibc libraries, so it doesn't
        needtobe installed specifically on Linux. It now seems a partofthe
        official UNIXspecification. Here is one implementation
        ofthelibrarywhich source can be found here.
Make check fails on some platforms
    Sometimes the regression tests' results don't completely matchthevalue
    produced by the parser, and the makefile uses diff to printthedelta. On
    some platforms the diff return breaks the compilationprocess;if the diff
    is small this is probably not a serious problem. Sometimes (especially on Solaris) make checks fail due tolimitationsin
    make. Try using GNU-make instead.I use the CVS version and there is no configure script
    The configure script (and other Makefiles) are generated.
    Usetheautogen.sh script to regenerate the configure script
    andMakefiles,like: ./autogen.sh --prefix=/usr --disable-shared
I have troubles when running make tests with gcc-3.0
    It seems the initial release of gcc-3.0 has a problem withtheoptimizer
    which miscompiles the URI module. Please useanothercompiler.
 Troubles compiling or linking programs using libxml2
    Usually the problem comes from the fact that the compiler
    doesn'tgetthe right compilation or linking flags. There is a small
    shellscriptxml2-configwhich is installed as part of
    libxml2usualinstall process which provides those flags. Use xml2-config --cflags
 to get the compilation flags and xml2-config --libs
 to get the linker flags. Usually this is done directly fromtheMakefile
    as: CFLAGS=`xml2-config --cflags`
 LIBS=`xml2-config --libs`
I want to install my own copy of libxml2 in my home
    directoryandlink my programs against it, but it doesn't work
    There are many different ways to accomplish this.  Here is one waytodo
    this under Linux.  Suppose your home directory
    is/home/user.Then: Create a subdirectory, let's call it myxmlunpack the libxml2 distribution into that subdirectorychdir into the unpacked
        distribution(/home/user/myxml/libxml2)configure the library using the
        "--prefix"switch,specifying an installation
        subdirectoryin/home/user/myxml, e.g../configure
        --prefix/home/user/myxml/xmlinst{otherconfiguration
        options}
now run makefollowed bymake installAt this point, the installation subdirectory contains
        thecomplete"private" include files, library files and binary
        programfiles (e.g.xmllint), located in
        respectively./home/user/myxml/xmlinst/lib,/home/user/myxml/xmlinst/includeand/home/user/myxml/xmlinst/bin
In order to use this "private" library, you should first add
        ittothe beginning of your default PATH (so that your own
        privateprogramfiles such as xmllint will be used instead of the
        normalsystemones).  To do this, the Bash command would be
        export PATH=/home/user/myxml/xmlinst/bin:$PATH
Now suppose you have a program test1.cthat
        youwouldlike to compile with your "private" library.  Simply compile
        itusingthe commandNote that, because your PATH has been set
        withgcc `xml2-config --cflags --libs` -o test test.c
 /home/user/myxml/xmlinst/binat the beginning,
        thexml2-configprogram which you just installed will be used instead
        ofthe systemdefault one, and this will automaticallyget
        thecorrectlibraries linked with your program.
xmlDocDump() generates output on one line.
    Libxml2 will not inventspaces in the content
    ofadocument since all spaces in the content of a
    documentaresignificant. If you build a tree from the API
    andwantindentation: the correct way is to generate those yourself too.the dangerous way is to ask libxml2 to add those blanks
        toyourcontent modifying the content of your document
        intheprocess. The result may not be what you expect.
        ThereisNOway to guarantee that such a
        modificationwon'taffect other parts of the content of your document.
        See xmlKeepBlanksDefault()andxmlSaveFormatFile()
Extra nodes in the document:
    For a XML file as below: <?xml version="1.0"?>
<PLAN xmlns="http://www.argus.ca/autotest/1.0/">
<NODE CommFlag="0"/>
<NODE CommFlag="1"/>
</PLAN> after parsing it with
    thefunctionpxmlDoc=xmlParseFile(...); I want to the get the content of the first node (node
    withtheCommFlag="0") so I did it as following; xmlNodePtr pnode;
pnode=pxmlDoc->children->children; but it does not work. If I change it to pnode=pxmlDoc->children->children->next; then it works.  Can someone explain it to me. In XML all characters in the content of the document
    aresignificantincluding blanks and formatting
    linebreaks. The extra nodes you are wondering about are just that, text
    nodeswiththe formatting spaces which are part of the document but that
    peopletendto forget. There is a function xmlKeepBlanksDefault()toremove
    those at parse time, but that's an heuristic, and itsuse should belimited
    to cases where you are certain there is nomixed-content in
    thedocument.I get compilation errors of existing code like
    whenaccessingrootor child
    fieldsofnodes.
    You are compiling code developed for libxml version 1 and
    usingalibxml2 development environment. Either switch back to libxml v1
    develoreven better fix the code to compile with libxml2 (or both) by following the instructions.I get compilation errors about
    nonexistingxmlRootNodeorxmlChildrenNodefields.
    The source code you are using has been upgradedto be able to compile with both
    libxmlandlibxml2, but you need to install a more recent
    version:libxml(-devel)>= 1.8.8 or libxml2(-devel) >= 2.1.0XPath implementation looks seriously broken
    XPath implementation prior to 2.3.0 was really incomplete. Upgrade
    toarecent version, there are no known bugs in the current version.The example provided in the web page does not compile.
    It's hard to maintain the documentation in sync with
    thecode<grin/> ... Check the previous points 1/ and 2/ raised before, and
    pleasesendpatches.Where can I get more examples and information than provided
    ontheweb page?
    Ideally a libxml2 book would be nice. I have no such plan ...
    Butyoucan: check more deeply the existinggenerated dochave a look at the
      setofexamples.look for examples of use for libxml2 function using the
        Gnomecode.For example the following will query the full Gnome CVS
        base fortheuse of the xmlAddChild()function:
        http://cvs.gnome.org/lxr/search?string=xmlAddChild This may be slow, a large hardware donation to the
        gnomeprojectcould cure this :-)Browsethelibxml2
        source, I try to write code as clean and documentedaspossible, so
        looking at it may be helpful. In particular the codeofxmllint.c and
        of the various testXXX.c test programs shouldprovidegood examples of
        how to do things with the library.
What about C++ ?
    libxml2 is written in pure C in order to allow easy reuse on anumberof
    platforms, including embedded systems. I don't intend to converttoC++. There is however a C++ wrapper which may fulfill your needs:How to validate a document a posteriori ?
    It is possible to validate documents which had not been
    validatedatinitial parsing time or documents which have been built
    fromscratchusing the API. Use the xmlValidateDtd()function.It
    is also possible to simply add a DTD to an existingdocument: xmlDocPtr doc; /* your existing document */
xmlDtdPtr dtd = xmlParseDTD(NULL, filename_of_dtd); /* parse the DTD */
        dtd->name = xmlStrDup((xmlChar*)"root_name"); /* use the given root */
        doc->intSubset = dtd;
        if (doc->children == NULL) xmlAddChild((xmlNodePtr)doc, (xmlNodePtr)dtd);
        else xmlAddPrevSibling(doc->children, (xmlNodePtr)dtd);
          So what is this funky "xmlChar" used all the time?
    It is a null terminated sequence of utf-8 characters. And
    onlyutf-8!You need to convert strings encoded in different ways to
    utf-8beforepassing them to the API.  This can be accomplished with the
    iconvlibraryfor instance.etc ...
 Daniel Veillard | 
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