libstdc++-v3/doc/html/manual/configure.html

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   3   When configuring libstdc++, you'll have to configure the entire
   4   <span class="emphasis"><em>gccsrcdir</em></span> directory. Consider using the
   5   toplevel gcc configuration option
   6   <code class="literal">--enable-languages=c++</code>, which saves time by only
   7   building the C++ toolchain.
   8 </p><p>
   9   Here are all of the configure options specific to libstdc++.  Keep
  10   in mind that
  11
  12    <a class="link" href="http://sourceware.org/autobook/autobook/autobook_14.html" target="_top">they
  13    all have opposite forms as well</a> (enable/disable and
  14    with/without).  The defaults are for the <span class="emphasis"><em>current
  15    development sources</em></span>, which may be different than those
  16    for released versions.
  17 </p><p>The canonical way to find out the configure options that are
  18    available for a given set of libstdc++ sources is to go to the
  19    source directory and then type: <span class="command"><strong>./configure --help</strong></span>.
  20 </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="code">--enable-multilib</code>[default]</span></dt><dd><p>This is part of the generic multilib support for building cross
  21         compilers.  As such, targets like "powerpc-elf" will have
  22         libstdc++ built many different ways:  "-msoft-float"
  23         and not, etc.  A different libstdc++ will be built for each of
  24         the different multilib versions.  This option is on by default.
  25      </p></dd><dt><span class="term"><code class="code">--enable-sjlj-exceptions</code></span></dt><dd><p>Forces old, set-jump/long-jump exception handling model.  If
  26         at all possible, the new, frame unwinding exception handling routines
  27         should be used instead, as they significantly reduce both
  28         runtime memory usage and executable size. This option can
  29         change the library ABI.
  30      </p></dd><dt><span class="term"><code class="code">--enable-version-specific-runtime-libs</code></span></dt><dd><p>Specify that run-time libraries should be installed in the
  31         compiler-specific subdirectory (i.e.,
  32         <code class="code">${libdir}/gcc-lib/${target_alias}/${gcc_version}</code>)
  33         instead of <code class="code">${libdir}</code>.  This option is useful if you
  34         intend to use several versions of gcc in parallel.  In addition,
  35         libstdc++'s include files will be installed in
  36         <code class="code">${libdir}/gcc-lib/${target_alias}/${gcc_version}/include/g++</code>,
  37         unless you also specify
  38        <code class="literal">--with-gxx-include-dir=</code><code class="filename">dirname</code> during configuration.
  39      </p></dd><dt><span class="term"><code class="code">--with-gxx-include-dir=&lt;include-files dir&gt;</code></span></dt><dd><p>Adds support for named libstdc++ include directory.  For instance,
  40         the following puts all the libstdc++ headers into a directory
  41         called "4.4-20090404" instead of the usual
  42         "c++/(version)".
  43      </p><pre class="programlisting">
  44    --with-gxx-include-dir=/foo/H-x86-gcc-3-c-gxx-inc/include/4.4-20090404</pre></dd><dt><span class="term"><code class="code">--enable-cstdio</code></span></dt><dd><p>This is an abbreviated form of <code class="code">'--enable-cstdio=stdio'</code>
  45         (described next).
  46      </p></dd><dt><span class="term"><code class="code">--enable-cstdio=OPTION</code></span></dt><dd><p>Select a target-specific I/O package. At the moment, the only
  47         choice is to use 'stdio', a generic "C" abstraction.
  48         The default is 'stdio'. This option can change the library ABI.
  49      </p></dd><dt><span class="term"><code class="code">--enable-clocale</code></span></dt><dd><p>This is an abbreviated form of <code class="code">'--enable-clocale=generic'</code>
  50         (described next).
  51      </p></dd><dt><span class="term"><code class="code">--enable-clocale=OPTION</code></span></dt><dd><p>Select a target-specific underlying locale package.  The
  52         choices are 'ieee_1003.1-2001' to specify an X/Open, Standard Unix
  53         (IEEE Std. 1003.1-2001) model based on langinfo/iconv/catgets,
  54         'gnu' to specify a model based on functionality from the GNU C
  55         library (langinfo/iconv/gettext) (from <a class="link" href="https://www.gnu.org/software/libc/" target="_top">glibc</a>, the GNU C
  56         library), 'generic' to use a generic "C" abstraction which consists
  57         of "C" locale info, 'newlib' to specify the Newlib C library model
  58         which only differs from the 'generic' model in the handling of
  59         ctype, or 'darwin' which omits the <span class="type">wchar_t</span> specializations
  60         needed by the 'generic' model.
  61      </p><p>If not explicitly specified, the configure process tries
  62       to guess the most suitable package from the choices above. The
  63       default is 'generic'. On glibc-based systems of sufficient
  64       vintage (2.3 and newer), 'gnu' is automatically selected. On newlib-based
  65       systems (<code class="code">'--with_newlib=yes'</code>) and OpenBSD, 'newlib' is
  66       automatically selected. On Mac OS X 'darwin' is automatically selected.
  67       This option can change the library ABI.
  68      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-allocator</code></span></dt><dd><p>This is an abbreviated form of
  69         <code class="code">'--enable-libstdcxx-allocator=auto'</code> (described
  70         next).
  71      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-allocator=OPTION  </code></span></dt><dd><p>Select a target-specific underlying std::allocator.  The
  72         choices are 'new' to specify a wrapper for new, 'malloc' to
  73         specify a wrapper for malloc, 'mt' for a fixed power of two allocator,
  74         'pool' for the SGI pooled allocator or 'bitmap' for a bitmap allocator.
  75         See this page for more information on allocator
  76         <a class="link" href="memory.html#allocator.ext" title="Extension Allocators">extensions</a>. This option
  77         can change the library ABI.
  78      </p></dd><dt><span class="term"><code class="code">--enable-cheaders=OPTION</code></span></dt><dd><p>This allows the user to define the approach taken for C header
  79         compatibility with C++. Options are c, c_std, and c_global.
  80         These correspond to the source directory's include/c,
  81         include/c_std, and include/c_global, and may also include
  82         include/c_compatibility.  The default is 'c_global'.
  83      </p></dd><dt><span class="term"><code class="code">--enable-threads</code></span></dt><dd><p>This is an abbreviated form of <code class="code">'--enable-threads=yes'</code>
  84         (described next).
  85      </p></dd><dt><span class="term"><code class="code">--enable-threads=OPTION</code></span></dt><dd><p>Select a threading library.  A full description is
  86         given in the
  87         general <a class="link" href="http://gcc.gnu.org/install/configure.html" target="_top">compiler
  88         configuration instructions</a>. This option can change the
  89         library ABI.
  90      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-threads</code></span></dt><dd><p>Enable C++11 threads support.  If not explicitly specified,
  91         the  configure process enables it if possible.  This
  92         option can change the library ABI.
  93      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-time</code></span></dt><dd><p>This is an abbreviated form of
  94         <code class="code">'--enable-libstdcxx-time=yes'</code>(described next).
  95      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-time=OPTION</code></span></dt><dd><p>Enables link-type checks for the availability of the
  96         clock_gettime clocks, used in the implementation of [time.clock],
  97         and of the nanosleep and sched_yield functions, used in the
  98         implementation of [thread.thread.this] of the 2011 ISO C++ standard.
  99         The choice OPTION=yes checks for the availability of the facilities
 100         in libc and libposix4.  In case it's needed the latter is also linked
 101         to libstdc++ as part of the build process.  OPTION=rt also searches
 102         (and, if needed, links) librt.   Note that the latter is not always
 103         desirable because, in glibc, for example, in turn it triggers the
 104         linking of libpthread too, which activates locking, a large overhead
 105         for single-thread programs.  OPTION=no skips the tests completely.
 106         The default is OPTION=auto, which skips the checks and enables the
 107         features only for targets known to support them.
 108     </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-debug</code></span></dt><dd><p>Build separate debug libraries in addition to what is normally built.
 109         By default, the debug libraries are compiled with
 110         <code class="code"> CXXFLAGS='-g3 -O0 -fno-inline'</code>
 111         , are installed in <code class="code">${libdir}/debug</code>, and have the
 112         same names and versioning information as the non-debug
 113         libraries. This option is off by default.
 114      </p><p>Note this make command, executed in
 115         the build directory, will do much the same thing, without the
 116         configuration difference and without building everything twice:
 117         <code class="code">make CXXFLAGS='-g3 -O0 -fno-inline' all</code>
 118      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-debug-flags=FLAGS</code></span></dt><dd><p>This option is only valid when <code class="code"> --enable-debug </code>
 119         is also specified, and applies to the debug builds only. With
 120         this option, you can pass a specific string of flags to the
 121         compiler to use when building the debug versions of libstdc++.
 122         FLAGS is a quoted string of options, like
 123      </p><pre class="programlisting">
 124   --enable-libstdcxx-debug-flags='-g3 -O1 -fno-inline'</pre></dd><dt><span class="term"><code class="code">--enable-cxx-flags=FLAGS</code></span></dt><dd><p>With this option, you can pass a string of -f (functionality)
 125         flags to the compiler to use when building libstdc++. This
 126         option can change the library ABI. FLAGS is a quoted string of
 127         options, like
 128      </p><pre class="programlisting">
 129   --enable-cxx-flags='-fvtable-gc -fomit-frame-pointer -ansi'</pre><p>
 130         Note that the flags don't necessarily have to all be -f flags,
 131         as shown, but usually those are the ones that will make sense
 132         for experimentation and configure-time overriding.
 133      </p><p>The advantage of --enable-cxx-flags over setting CXXFLAGS in
 134         the 'make' environment is that, if files are automatically
 135         rebuilt, the same flags will be used when compiling those files
 136         as well, so that everything matches.
 137      </p><p>Fun flags to try might include combinations of
 138      </p><pre class="programlisting">
 139   -fstrict-aliasing
 140   -fno-exceptions
 141   -ffunction-sections
 142   -fvtable-gc</pre><p>and opposite forms (-fno-) of the same.  Tell us (the libstdc++
 143         mailing list) if you discover more!
 144      </p></dd><dt><span class="term"><code class="code">--enable-c99</code></span></dt><dd><p>The <span class="type">long long</span> type was introduced in C99, along
 145         with many other functions for wide characters, and math
 146         classification macros, etc.  If enabled, all C99 functions not
 147         specified by the C++ standard will be put into <code class="code">namespace
 148         __gnu_cxx</code>, and then all these names will
 149         be injected into namespace std, so that C99 functions can be
 150         used "as if" they were in the C++ standard (as they
 151         will eventually be in some future revision of the standard,
 152         without a doubt).  By default, C99 support is on, assuming the
 153         configure probes find all the necessary functions and bits
 154         necessary. This option can change the library ABI.
 155     </p></dd><dt><span class="term"><code class="code">--enable-wchar_t</code>[default]</span></dt><dd><p>Template specializations for the <span class="type">wchar_t</span> type are
 156         required for wide character conversion support.  Disabling
 157         wide character specializations may be expedient for initial
 158         porting efforts, but builds only a subset of what is required by
 159         ISO, and is not recommended.  By default, this option is on.
 160         This option can change the library ABI.
 161      </p></dd><dt><span class="term"><code class="code">--enable-long-long  </code></span></dt><dd><p>The <span class="type">long long</span> type was introduced in C99.  It is
 162         provided as a GNU extension to C++98 in g++.  This flag builds
 163         support for "long long" into the library (specialized
 164         templates and the like for iostreams).  This option is on by default:
 165         if enabled, users will have to either use the new-style "C"
 166         headers by default (i.e., &lt;cmath&gt; not &lt;math.h&gt;)
 167         or add appropriate compile-time flags to all compile lines to
 168         allow "C" visibility of this feature (on GNU/Linux,
 169         the flag is -D_ISOC99_SOURCE, which is added automatically via
 170         CPLUSPLUS_CPP_SPEC's addition of _GNU_SOURCE).
 171         This option can change the library ABI.
 172      </p></dd><dt><span class="term"><code class="code">--enable-fully-dynamic-string</code></span></dt><dd><p>This option enables a special version of basic_string avoiding
 173         the optimization that allocates empty objects in static memory.
 174         Mostly useful together with shared memory allocators, see PR
 175         libstdc++/16612 for details.
 176      </p></dd><dt><span class="term"><code class="code">--enable-concept-checks</code></span></dt><dd><p>This turns on additional compile-time checks for instantiated
 177         library templates, in the form of specialized templates,
 178         <a class="link" href="concept_checking.html" title="Concept Checking">described here</a>.  They
 179         can help users discover when they break the rules of the STL, before
 180         their programs run.
 181      </p></dd><dt><span class="term"><code class="code">--enable-symvers[=style]</code></span></dt><dd><p>In 3.1 and later, tries to turn on symbol versioning in the
 182         shared library (if a shared library has been
 183         requested). Values for 'style' that are currently supported
 184         are 'gnu', 'gnu-versioned-namespace', 'darwin',
 185         'darwin-export', and 'sun'. Both gnu- options require that a recent
 186         version of the GNU linker be in use. Both darwin options are
 187         equivalent. With no style given, the configure script will try
 188         to guess correct defaults for the host system, probe to see if
 189         additional requirements are necessary and present for
 190         activation, and if so, will turn symbol versioning on. This
 191         option can change the library ABI.
 192      </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-visibility</code></span></dt><dd><p> In 4.2 and later, enables or disables visibility
 193         attributes. If enabled (as by default), and the compiler seems
 194         capable of passing the simple sanity checks thrown at it, adjusts
 195         items in namespace std, namespace std::tr1, namespace std::tr2,
 196         and namespace __gnu_cxx to have <code class="code">visibility ("default")</code>
 197         so that -fvisibility options can be used without affecting the
 198         normal external-visibility of namespace std entities.
 199         Prior to 4.7 this option was spelled <code class="code">--enable-visibility</code>.
 200     </p></dd><dt><span class="term"><code class="code">--enable-libstdcxx-pch</code></span></dt><dd><p>In 3.4 and later, tries to turn on the generation of
 201         stdc++.h.gch, a pre-compiled file including all the standard
 202         C++ includes. If enabled (as by default), and the compiler
 203         seems capable of passing the simple sanity checks thrown at
 204         it, try to build stdc++.h.gch as part of the make process.
 205         In addition, this generated file is used later on (by appending <code class="code">
 206         --include bits/stdc++.h </code> to CXXFLAGS) when running the
 207         testsuite.
 208      </p></dd><dt><span class="term"><code class="code">--enable-extern-template</code>[default]</span></dt><dd><p>Use extern template to pre-instantiate all required
 209         specializations for certain types defined in the standard libraries.
 210         These types include <code class="classname">string</code> and dependents like
 211         <code class="classname">char_traits</code>, the templatized IO classes,
 212         <code class="classname">allocator</code>, and others.
 213         Disabling means that implicit
 214         template generation will be used when compiling these types.  By
 215         default, this option is on. This option can change the library ABI.
 216      </p></dd><dt><span class="term"><code class="code">--disable-hosted-libstdcxx</code></span></dt><dd><p>
 217      By default, a complete <span class="emphasis"><em>hosted</em></span> C++ library is
 218      built.  The C++ Standard also describes a
 219      <span class="emphasis"><em>freestanding</em></span> environment, in which only a
 220      minimal set of headers are provided.  This option builds such an
 221      environment.
 222      </p></dd><dt><span class="term"><code class="code">--disable-libstdcxx-verbose</code></span></dt><dd><p>
 223      By default, the library is configured to write descriptive messages
 224      to standard error for certain events such as calling a pure virtual
 225      function or the invocation of the standard terminate handler.  Those
 226      messages cause the library to depend on the demangler and standard I/O
 227      facilities, which might be undesirable in a low-memory environment or
 228      when standard error is not available.  This option disables those
 229      messages.  This option does not change the library ABI.
 230    </p></dd><dt><span class="term"><code class="code">--enable-vtable-verify</code>[default]</span></dt><dd><p>Use <code class="code">-fvtable-verify=std</code> to compile the C++
 231     runtime with instrumentation for vtable verification. All virtual
 232     functions in the standard library will be verified at runtime.
 233     Types impacted include <code class="classname">locale</code> and
 234     <code class="classname">iostream</code>, and others.  Disabling means that
 235     the C++ runtime is compiled without support for vtable
 236     verification. By default, this option is off.
 237      </p></dd></dl></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="setup.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="setup.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="make.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 2. Setup </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Make</td></tr></table></div></body></html>