<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../general.ent">
  %general-entities;
]>

<sect1 id="ch-system-libffi" role="wrap">
  <?dbhtml filename="libffi.html"?>

  <sect1info condition="script">
    <productname>libffi</productname>
    <productnumber>&libffi-version;</productnumber>
    <address>&libffi-url;</address>
  </sect1info>

  <title>Libffi-&libffi-version;</title>

  <indexterm zone="ch-system-libffi">
    <primary sortas="a-libffi">libffi</primary>
  </indexterm>

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

    <para>The Libffi library provides a portable, high level programming
    interface to various calling conventions. This allows a programmer to call
    any function specified by a call interface description at run time.</para>

    <segmentedlist>
      <segtitle>&buildtime;</segtitle>
      <segtitle>&diskspace;</segtitle>

      <seglistitem>
        <seg>&libffi-ch6-sbu;</seg>
        <seg>&libffi-ch6-du;</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

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

    <note>
      <para>Similar to GMP, libffi builds with optimizations specific
      to the proccesor in use. If building for another system, export
      CFLAGS and CXXFLAGS to specify a generic build for your architecture.
      If this is not done, all applications that link to libffi will trigger
      Illegal Operation Errors.</para>
    </note>

    <para>Modify the Makefile to install headers into the standard
    <filename class="directory">/usr/include</filename> directory instead of
    <filename class="directory">/usr/lib/libffi-&libffi-version;/include</filename>.</para>

<screen><userinput remap="pre">sed -e '/^includesdir/ s/$(libdir).*$/$(includedir)/' \
    -i include/Makefile.in

sed -e '/^includedir/ s/=.*$/=@includedir@/' \
    -e 's/^Cflags: -I${includedir}/Cflags:/' \
    -i libffi.pc.in</userinput></screen>

    <para>Prepare libffi for compilation:</para>

<screen><userinput remap="configure">./configure --prefix=/usr --disable-static --with-gcc-arch=native</userinput></screen>

    <variablelist>
      <title>The meaning of the configure option:</title>

      <varlistentry>
        <term><parameter>--with-gcc-arch=native</parameter></term>
        <listitem>
          <para>Ensure gcc optimizes for the current system.  If this
          is not specified, the system is guessed and the code generated
          may not be correct for some systems.  If the generated code
          will be copied from the native system to a less capable 
          system, use the less capable system as a parameter. For details 
          about alternative system types, see <ulink 
          url='https://gcc.gnu.org/onlinedocs/gcc-&gcc-version;/gcc/x86-Options.html'>
          the x86 options in the gcc manual</ulink>.</para>
        </listitem>
      </varlistentry>

    </variablelist>

    <para>Compile the package:</para>

<screen><userinput remap="make">make</userinput></screen>

    <para>To test the results, issue:</para>

<screen><userinput remap="test">make check</userinput></screen>

    <para>Install the package:</para>

<screen><userinput remap="install">make install</userinput></screen>

  </sect2>

  <sect2 id="contents-libffi" role="content">
    <title>Contents of Libffi</title>

    <segmentedlist>
      <segtitle>Installed library</segtitle>

      <seglistitem>
        <seg>libffi.so</seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="libffi">
        <term><filename class="libraryfile">libffi</filename></term>
        <listitem>
          <para>contains the libffi API functions.</para>
          <indexterm zone="ch-system-libffi">
            <primary sortas="c-libffi">libffi</primary>
          </indexterm>
        </listitem>
      </varlistentry>
    </variablelist>

  </sect2>

</sect1>

