source: clfs-embedded/BOOK/cross-tools/x86/uclibc.xml@ 3be2fca

<?xml version="1.0" encoding="ISO-8859-1"?>
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  "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
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<sect1 id="ch-cross-tools-uclibc" role="wrap">
  <?dbhtml filename="uclibc.html"?>

  <title>uClibc-&uclibc-version;</title>

  <indexterm zone="ch-cross-tools-uclibc">
    <primary sortas="a-uClibc">uClibc</primary>
    <secondary>cross tools</secondary>
  </indexterm>

  <sect2 role="package">
    <title/>

    <para>The uClibc package contains the main C library. This library provides
    the basic routines for allocating memory, searching directories, opening and
    closing files, reading and writing files, string handling, pattern matching,
    arithmetic, and so on.</para>

  </sect2>

  <sect2 role="installation">
    <title>Installation of uClibc</title>

    <para os="c">By default uClibc symlinks the headers to the source directory.
    This is not acceptable in our build scenario, so we modify the Makefiles
    so that the headers will be copied instead:</para>

<screen os="d"><userinput>cp Makefile Makefile.orig
sed -e 's/$(LN) -fs/cp/g' Makefile.orig > Makefile
for file in `find libc/sysdeps/linux -name Makefile`; do
        cp $file $file.orig
        sed -e 's/$(LN) -fs/cp/g' -e 's@../libc/@$(TOPDIR)libc/@g' $file.orig > $file
done</userinput></screen>

    <note os="e">
      <para>Below we are just telling uClibc to use its default configuration.
      For those for more adventureous, you can use make menuconfig, and
      do a more custom build for your uClibc installation.</para>
    </note>

    <para os="f">Create the default configuration:</para>

<screen os="g"><userinput>make defconfig</userinput></screen>

   <para os="h">We will need to edit the configuration file, to make sure everything gets
   compiled and put into its proper location:</para>

<screen os="i"><userinput>cp .config .config.orig
sed -e "/^CROSS_COMPILER_PREFIX/s:=.*:=\"${CLFS_TARGET}-\":" \
    -e "/^KERNEL_SOURCE/s:=.*:=\"${CLFS}/usr\":" \
    -e "/^SHARED_LIB_LOADER_PREFIX/s:=.*:=\"/lib\":" \
    -e "/^DEVEL_PREFIX/s:=.*:=\"/usr\":" \
    -e "/^RUNTIME_PREFIX/s:=.*:=\"/\":" \
    .config.orig > .config</userinput></screen>

    <para os="j">We will need to make sure that some settings in uClibc are set so we
    can utilize all the features of BusyBox:</para>

<screen os="k"><userinput>UCLIBC_OPTIONS="DO_C99_MATH UCLIBC_HAS_RPC UCLIBC_HAS_CTYPE_CHECKED
                UCLIBC_HAS_WCHAR UCLIBC_HAS_HEXADECIMAL_FLOATS UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
                UCLIBC_HAS_PRINTF_M_SPEC UCLIBC_HAS_FTW UCLIBC_HAS_IPV6 UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
                UCLIBC_USE_NETLINK LDSO_PRELOAD_FILE_SUPPORT"
for config in $UCLIBC_OPTIONS; do
        cp .config .config.orig
        sed -e "s:# ${config} is not set:${config}=y:" .config.orig > .config
done
echo "UCLIBC_HAS_FULL_RPC=y" >> .config
echo "UCLIBC_HAS_REENTRANT_RPC=y" >> .config</userinput></screen>

    <para os="l">We have made some changes to our config, let's make sure
    that we didn't miss and dependencies:</para>

<screen os="m"><userinput>make TARGET_ARCH=i386 oldconfig</userinput></screen>

    <para os="n">Compile the package:</para>

<screen os="o"><userinput>make CC="${CC} ${BUILD}" TARGET_ARCH=i386</userinput></screen>

   <para os="p">The uClibc build system creates symlinks in its
   <filename class="directory">include</filename> directory pointing to
   ${CLFS}/usr/include. We will need to remove these symlinks from the source dir:</para>

<screen os="q"><userinput>rm include/{asm,asm-generic,linux}</userinput></screen>

    <para os="r">Install the package:</para>

<screen os="s"><userinput>make PREFIX=${CLFS} install</userinput></screen>

  </sect2>

  <sect2 id="contents-uclibc" role="content">
    <title>Contents of uClibc</title>

    <segmentedlist>
      <segtitle>Installed uClibc</segtitle>

      <seglistitem>
        <seg>To Be Written</seg>
      </seglistitem>
    </segmentedlist>
<!--
    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

     <varlistentry id="uclibc">
        <term><filename
        class="headerfile">/usr/include/{asm,linux}/*.h</filename></term>
        <listitem>
          <para>The Linux API headers</para>
          <indexterm zone="ch-system-linux-headers linux-headers">
            <primary
            sortas="e-/usr/include/{asm,linux}/*.h">/usr/include/{asm,linux}/*.h</primary>
          </indexterm>
        </listitem>
      </varlistentry>
    </variablelist>
-->

  </sect2>
</sect1>