<section xmlns="http://docbook.org/ns/docbook" version="5.0"
xml:id="manual.intro.setup.prereq" xreflabel="Prerequisites">
<?dbhtml filename="prerequisites.html"?>
<info><title>Prerequisites</title>
<keywordset>
<keyword>ISO C++</keyword>
<keyword>Prerequisites</keyword>
</keywordset>
</info>
<para>
Because libstdc++ is part of GCC, the primary source for
installation instructions is
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/install/">the GCC install page</link>.
In particular, list of prerequisite software needed to build the library
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/install/prerequisites.html">
starts with those requirements.</link> The same pages also list
the tools you will need if you wish to modify the source.
</para>
<para>
Additional data is given here only where it applies to libstdc++.
</para>
<para>As of GCC 4.0.1 the minimum version of binutils required to build
libstdc++ is <code>2.15.90.0.1.1</code>.
Older releases of libstdc++ do not require such a recent version,
but to take full advantage of useful space-saving features and
bug-fixes you should use a recent binutils whenever possible.
The configure process will automatically detect and use these
features if the underlying support is present.
</para>
<para>
To generate the API documentation from the sources you will need
Doxygen, see <link linkend="appendix.porting.doc">Documentation
Hacking</link> in the appendix for full details.
</para>
<para>
Finally, a few system-specific requirements:
</para>
<variablelist>
<varlistentry>
<term>linux</term>
<listitem>
<para>
The 'gnu' locale model makes use of <function>iconv</function>
for character set conversions. The relevant functions are provided
by Glibc and so are always available, however they can also be
provided by the separate GNU libiconv library. If GNU libiconv is
found when GCC is built (e.g., because its headers are installed
in <filename class="directory">/usr/local/include</filename>)
then the <filename>libstdc++.so.6</filename> library will have a
run-time dependency on <filename>libiconv.so.2</filename>.
If you do not want that run-time dependency then you should do
one of the following:
</para>
<itemizedlist>
<listitem>
<para>
Uninstall the libiconv headers before building GCC.
Glibc already provides <function>iconv</function> so you should
not need libiconv anyway.
</para>
</listitem>
<listitem>
<para>
<link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="https://www.gnu.org/software/libiconv/#downloading">
Download</link> the libiconv sources and extract them into the
top level of the GCC source tree, e.g.,
</para>
<programlisting>
wget https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.16.tar.gz
tar xf libiconv-1.16.tar.gz
ln -s libiconv-1.16 libiconv
</programlisting>
<para>
This will build libiconv as part of building GCC and link to
it statically, so there is no <filename>libiconv.so.2</filename>
dependency.
</para>
</listitem>
<listitem>
<para>
Configure GCC with <option>--with-libiconv-type=static</option>.
This requires the static <filename>libiconv.a</filename> library,
which is not installed by default. You might need to reinstall
libiconv using the <option>--enable-static</option> configure
option to get the static library.
</para>
</listitem>
</itemizedlist>
</listitem>
<listitem>
<para>
If GCC 3.1.0 or later on is being used on GNU/Linux, an attempt
will be made to use "C" library functionality necessary for
C++ named locale support. For GCC 4.6.0 and later, this
means that glibc 2.3 or later is required.
</para>
<para>
If the 'gnu' locale model is being used, the following
locales are used and tested in the libstdc++ testsuites.
The first column is the name of the locale, the second is
the character set it is expected to use.
</para>
<programlisting>
de_DE ISO-8859-1
de_DE@euro ISO-8859-15
en_GB ISO-8859-1
en_HK ISO-8859-1
en_PH ISO-8859-1
en_US ISO-8859-1
en_US.ISO-8859-1 ISO-8859-1
en_US.ISO-8859-15 ISO-8859-15
en_US.UTF-8 UTF-8
es_ES ISO-8859-1
es_MX ISO-8859-1
fr_FR ISO-8859-1
fr_FR@euro ISO-8859-15
is_IS UTF-8
it_IT ISO-8859-1
ja_JP.eucjp EUC-JP
ru_RU.ISO-8859-5 ISO-8859-5
ru_RU.UTF-8 UTF-8
se_NO.UTF-8 UTF-8
ta_IN UTF-8
zh_TW BIG5
</programlisting>
<para>Failure to have installed the underlying "C" library
locale information for any of the above regions means that
the corresponding C++ named locale will not work: because of
this, the libstdc++ testsuite will skip named locale tests
which need missing information. If this isn't an issue, don't
worry about it. If a named locale is needed, the underlying
locale information must be installed. Note that rebuilding
libstdc++ after "C" locales are installed is not necessary.
</para>
<para>
To install support for locales, do only one of the following:
</para>
<itemizedlist>
<listitem>
<para>install all locales</para>
</listitem>
<listitem>
<para>install just the necessary locales</para>
<itemizedlist>
<listitem>
<para>with Debian GNU/Linux:</para>
<para> Add the above list, as shown, to the file
<code>/etc/locale.gen</code> </para>
<para> run <code>/usr/sbin/locale-gen</code> </para>
</listitem>
<listitem>
<para>on most Unix-like operating systems:</para>
<para><code> localedef -i de_DE -f ISO-8859-1 de_DE </code></para>
<para>(repeat for each entry in the above list) </para>
</listitem>
<listitem>
<para>
Instructions for other operating systems solicited.
</para>
</listitem>
</itemizedlist>
</listitem>
</itemizedlist>
</listitem>
</varlistentry>
</variablelist>
</section>