gcc/libstdc++-v3/docs/install.html
Benjamin Kosnik 967add5195 install.html: Edit bits about requiring a special version of the autotools.
2000-08-01  Benjamin Kosnik  <bkoz@purist.soma.redhat.com>

	* docs/install.html: Edit bits about requiring a special version
	of the autotools.

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2000-08-01 18:07:23 +00:00

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<H1 CLASS="centered"><A NAME="top">libstdc++-v3 INSTALL</A></H1>
<P>The latest version of this document is always available at
<A HREF="http://sources.redhat.com/libstdc++/install.html">
http://sources.redhat.com/libstdc++/install.html</A>.
</P>
<P>To the <A HREF="index.html">libstdc++-v3 homepage</A>.
<!-- ####################################################### -->
<HR>
<H2>Contents</H2>
<UL>
<LI><A HREF="#prereqs">Tools you will need beforehand</A>
<LI><A HREF="#srcsetup">Setting up the source directories</A>
<LI><A HREF="#config">Configuring</A>
<LI><A HREF="#install">Building and installing the library</A>
<LI><A HREF="#postinstall">Post-installation</A>
<LI><A HREF="#usage">Using the library</A>
</UL>
<HR>
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<H2><A NAME="prereqs">Tools you will need beforehand</A></H2>
<P>You will need a recent version of g++ to compile the snapshot of
libstdc++: gcc-2.95.2 works well, or one of the post-2.95.2 egcs
snapshots (insert standard caveat about using snapshots rather
than formal releases). You will need the full source
distribution to whatever compiler release you are using. The
GCC snapshots can be had from one of the sites on their
<A HREF="http://gcc.gnu.org/mirrors.html">mirror list</A>.
</P>
<P>In addition, if you plan to modify the makefiles or regenerate
the configure scripts you'll need the nuevo automake, libtool
and autoconf to regenerate the Makefiles and configure
scripts. These tools are all required to be installed in the
same location (most linux distributions install these tools by
default, so no worries.)
</P>
<P>If you don't have bash, and want to run <TT>'make check'</TT> to
test your build, you'll need to get bash 2.x. Also recommended
is GNU Make, since it is the only 'make' that will parse these
makefiles correctly.
</P>
<P>As of June 19, 2000, libstdc++ attempts to use tricky and
space-saving features of the GNU toolchain, enabled with
<TT>-ffunction-sections -fdata-sections -Wl,--gc-sections</TT>.
To obtain maximum benefit from this, binutils after this date
should also be used (bugs were fixed with C++ exception handling
related to this change in libstdc++-v3). The version of these
tools should be <TT>2.10.90</TT>, and you can get snapshots (as
well as releases) of binutils
<A HREF="ftp://sources.redhat.com/pub/binutils">here</A>.
</P>
<P>Finally, if you are using Cygwin to compile libstdc++-v3 on
Win32, you'll have to get a version of the cygwin1.dll that is
dated on or after February 1, 2000. This is necessary to
successfully run the script "mknumeric_limits" which probes the
floating-point environment of the host in question -- before this
date, Cygwin would freeze when running this script. In addition,
you may want to get a current version of libtool (say
libtool-1.3.4 and above) as earlier versions supposedly had
problems creating shared libraries.
</P>
<HR>
<H2><A NAME="srcsetup">Setting up the source directories</A></H2>
<P><EM>As the libstdc++-v3 sources and the core GCC sources have
converged, more and more effort goes to building the
library as the default version to be shipped with g++. With the
2.90.8 snapshot, and especially for CVS versions after this
release, this is treated as the usual scenario. If you want to
build the library all by itself, you will need to explicitly
disable certain features (like namespaces) since the core GCC
library, libgcc.a, will not be rebuilt with those same features.
</EM>
</P>
<P>By default, all configurations of libstdc++-v3 now have namespaces
enabled. Being able to select/de-select this option was a complex task
that had hopelessly confused many otherwise intelligent people, and
provided an endless stream of silent cursing and cries for help.
Because of this, gcc sources are required, and are no longer optional.
</P>
<P>The following definitions will be used throughout the rest of this
document:
<UL>
<LI><EM>gccsrcdir</EM>: The directory holding the source of the
compiler. It should have several subdirectories like
<EM>gccsrcdir</EM>/libio and <EM>gccsrcdir</EM>/gcc.
<LI><EM>libsrcdir</EM>: The directory holding the source of the
C++ library.
<LI><EM>gccbuilddir</EM>: The build directory for the compiler
in <EM>gccsrcdir</EM>. GCC requires that it be built in
a different directory than its sources.
<LI><EM>libbuilddir</EM>: The build directory for libstdc++.
<LI><EM>destdir</EM>: The eventual installation directory for
the compiler/libraries, set with the --prefix option to
the configure script.
</UL>
Note:
<OL>
<LI>The .8 snapshot and following are intended to replace the
library that comes with the compiler, so <EM>libsrcdir</EM>
and <EM>libbuilddir</EM> must be contained under
<EM>gccsrcdir</EM> and <EM>gccbuilddir</EM>, respectively.
<LI>The source, build, and installation directories should
not be parents of one another; i.e., these should all be
separate directories. Please don't build out of the
source directory.
</OL>
</P>
<P>Since the release of libstdc++-2.90.8, configuration patches have gone
into CVS gcc that make the management of the various libstdc++ source
trees a bit easier. Because of this, both libstdc++-v2 and
libstdc++-v3 and live together more or less in peace, without the need
for soft linking. If a CVS gcc source directory after April 5, 2000 is
being used, then the directions are slightly different: please pick
which of the following two scenarios best represents your particular
situation.
</P>
<P><B>...with gcc-2.95.2</B>
<P>Unpack the <EM>gccsrcdir</EM> and go into that directory. For
instance, <TT>gcc-2.95.2</TT> is a valid <EM>gccsrcdir</EM>.
Once in <EM>gccsrcdir</EM>, you'll need to rename the directories
called <TT> libstdc++ </TT> and <TT> libio </TT> like so:
<PRE>
mv libstdc++ libstdc++-v2
mv libio libio-v2</PRE>
</P>
<P>Next, unpack the libstdc++-v3 library tarball into the
<EM>gccsrcdir</EM> directory; it will create a
<EM>libsrcdir</EM> called <TT>libstdc++-<EM>version</EM></TT>:
<PRE>
gzip -dc libstdc++-version.tar.gz | tar xf -</PRE>
</P>
<P>Finally, make a soft link between <EM>libsrcdir</EM> and
<TT>libstdc++</TT> so that libstdc++-v3 will be the default C++
library used.
<PRE>
ln -s <EM>libsrcdir</EM> libstdc++</PRE>
This complexity of having two completely separate libstdc++
libraries is necessary so that you can unlink <EM>libsrcdir</EM>
and update the compiler sources. If you're not this adventurous, or
would not like to switch between different C++ standard libraries,
this extra effort is probably wasted; just remove the v2 sources.
</P>
</P>
<P><B>...with CVS gcc</B>
<P>Check out or download the gcc sources: the resulting source
directory is <EM>gccsrcdir</EM>.
</P>
<P>Next, unpack the libstdc++-v3 library tarball into this
<EM>gccsrcdir</EM> directory; it will create a
<EM>libsrcdir</EM> called <TT>libstdc++-<EM>version</EM></TT>:
<PRE>
gzip -dc libstdc++-version.tar.gz | tar xf -</PRE>
</P>
<P>If CVS libstdc++-v3 is being used instead of a snapshot's tarball,
then move the source directory from the CVS checkout into the
<EM>gccsrcdir</EM> directory.
<P>Finally, rename <EM>libsrcdir</EM> to <TT>libstdc++-v3</TT> so that
gcc's configure flags will be able to deal with the new library.
<PRE>
mv <EM>libsrcdir</EM> libstdc++-v3</PRE>
</P>
</P>
<HR>
<H2><A NAME="config">Configuring</A></H2>
<P>Due to namespaces, when building libstdc++-v3 you'll have to configure
the entire <EM>gccsrcdir</EM> directory. The full list of libstdc++-v3
specific configuration options, not dependent on the specific compiler
release being used, can be found <A HREF="configopts.html">here</A>.
</P>
<P>Consider possibly using --enable-languages=c++ to save time by only
building the C++ language parts.
</P>
<P><B>...with gcc-2.95.2</B>
<PRE>
<EM>gccsrcdir</EM>/configure --prefix=<EM>destdir</EM></PRE>
</P>
<P><B>...with CVS gcc</B>
<PRE>
<EM>gccsrcdir</EM>/configure --prefix=<EM>destdir</EM> --enable-libstdcxx-v3</PRE>
</P>
<P>Adding <TT>--enable-libstdcxx-v3</TT> automatically selects libstdc++-v3
as the C++ library to be used alongside the C++ compiler being built,
and also enables -fhonor-std by default. This option is not available
with gcc-2.95.2.
</P>
<HR>
<H2><A NAME="install">Building and installing the library</A></H2>
<P>Now you have a few options:</P>
<H3>[re]building <EM>everything</EM></H3>
<P>If you're building GCC from scratch, you can do the usual
<TT> 'make bootstrap' </TT> here, and libstdc++-v3 will be built
as its default C++ library. The generated g++ will magically
use the correct headers, link against the correct library
binary, and in general using libstdc++-v3 will be a piece of
cake. You're done; run <TT>'make install'</TT> (the GCC
Installation instructions) to put the new compiler and libraries
into place.
</P>
<H3>[re]building only libstdc++</H3>
<P>Due to differences in the configure process, the resulting Makefiles
in the<EM>gccbuilddir</EM> will have different rules depending on
the source base being used.
</P>
<P><B>...with gcc-2.95.2</B>
<BLOCKQUOTE>
<EM>libstdc++-rule</EM> is <TT>libstdc++</TT>
</BLOCKQUOTE>
</P>
<P><B>...with CVS gcc</B>
<BLOCKQUOTE>
<EM>libstdc++-rule</EM> is <TT>libstdc++-v3</TT>
</BLOCKQUOTE>
</P>
<P>To rebuild just libstdc++, use:
<PRE>
make all-target-<EM>libstdc++-rule</EM></PRE>
This will configure and build the C++ library in the
<EM>gccbuilddir/cpu-vendor-OS/</EM>libstdc++ directory.
As en example, for CVS gcc this would be
<TT>make all-target-libstdc++-v3</TT>, and for gcc-2.95.2 it would be
<TT>make all-target-libstdc++</TT>
</P>
<P>If the build fails with a &quot;warning: can't inline call&quot;
message when compiling stringMAIN.cc, see <A HREF="#Werror">the
resolution at the end of this document</A>.
</P>
<P>If you are rebuilding from a previous build [attempt], some
information is kept in a cache file. This is stored in
<EM>gccbuilddir/cpu-vendor-OS/</EM> if you are building with
multilibs (the default), or in
<EM>gccbuilddir/cpu-vendor-OS/</EM>libstdc++-v3 if you have
multilibs disabled. The filename is config.cache; if previous
information is causing problems, you can delete it entirely, or
simply edit it and remove lines.
</P>
<P>You're done. Now install the rebuilt pieces with
<PRE>
make install</PRE>
or
<PRE>
make install-gcc
make install-target-<EM>libstdc++-rule</EM></PRE>
</P>
<HR>
<H2><A NAME="postinstall">Post-installation</A></H2>
<P>Installation will create the <EM>destdir</EM> directory and
populate it with subdirectories:
<PRE>
lib/
include/g++-v3/
bits/
backward/
ext/</PRE>
</P>
<P>You can check the status of the build without installing it using
<PRE>
make check</PRE>
or you can check the status of the installed library using
<PRE>
make check-target-<EM>libstdc++-rule</EM></PRE>
These commands will create a 'testsuite' directory underneath
<EM>libbuilddir</EM> containing the results of the tests. We are
interested in any strange failures of the testsuite; please see
<A HREF="faq/index.html#2_4">FAQ 2.4</A> for which files to examine.
</P>
<HR>
<H2><A NAME="usage">Using the library</A></H2>
<LI><B>Find the new library at runtime (shared linking only)</B>
<P>If you only built a static library (libstdc++.a), or if you
specified static linking, you don't have to worry about this.
But if you built a shared library (libstdc++.so) and linked
against it, then you will need to find that library when you
run the executable.
</P>
<P>Methods vary for different platforms and different styles, but
the usual ones are printed to the screen during installation.
They include:
<UL>
<LI>At runtime set LD_LIBRARY_PATH in your environment correctly,
so that the shared library for libstdc++ can be found and
loaded. Be certain that you understand all of the other
implications and behavior of LD_LIBRARY_PATH first (few
people do, and they get into trouble).
<LI>Compile the path to find the library at runtime into the
program. This can be done by passing certain options to g++,
which will in turn pass them on to the linker. The exact
format of the options is dependent on which linker you use:
<UL>
<LI>GNU ld (default on Linux):<TT> -Wl,--rpath -Wl,<EM>destdir</EM>/lib</TT>
<LI>IRIX ld:<TT> -Wl,-rpath -Wl,<EM>destdir</EM>/lib</TT>
<LI>Solaris ld:<TT> -Wl,-R<EM>destdir</EM>/lib</TT>
<LI>More...?
</UL>
</UL>
</P>
<P>Use the <TT>ldd(1)</TT> utility to show which library the system
thinks it will get at runtime.
</P>
</OL>
</P>
<HR>
<H3><A NAME="Werror"><TT>warning: can't inline call to</TT>...</A></H3>
<P>When building the .8 snapshot with g++ 2.95.2, compilation may halt
with this warning message. The &quot;problem&quot; is the -Werror
flag being passed to the compiler, which says to treat warnings as
errors. (This plus a high warning level makes us track down bugs
<EM>quickly</EM>.) The compiler can't inline a certain call, prints
a warning, and dies.
</P>
<P>The workaround is to edit either <EM>libsrcdir</EM>/src/Makefile.in
(before configuring) or <EM>bld-libstdc++</EM>/src/Makefile
(after configuring). There's one line that reads
<PRE>
WERROR = -Werror</PRE>
Delete the flag itself, so that the line reads
<PRE>
WERROR =</PRE>
Then the compiler will still print a warning, but it won't die.
</P>
<P>For the curious, this &quot;problem&quot; is actually a symptom
of something else. The compiler in CVS could inline more than what
2.95.2 does, and the libstdc++ changes were made with that
compiler. One of the libstdc++ maintainers explains this
<A HREF="http://sources.redhat.com/ml/libstdc++/2000-q1/msg00420.html">here</A>.
</P>
<P>This has been patched in current CVS sources.
</P>
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<P CLASS="fineprint"><EM>
Comments and suggestions are welcome, and may be sent to
<A HREF="mailto:pme@sources.redhat.com">Phil Edwards</A> or
<A HREF="mailto:gdr@egcs.cygnus.com">Gabriel Dos Reis</A>.
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