1*404b540aSrobert<?xml version="1.0" encoding="ISO-8859-1"?> 2*404b540aSrobert<!DOCTYPE html 3*404b540aSrobert PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 4*404b540aSrobert "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 5*404b540aSrobert 6*404b540aSrobert<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 7*404b540aSrobert<head> 8*404b540aSrobert <meta name="AUTHOR" content="pme@gcc.gnu.org (Phil Edwards)" /> 9*404b540aSrobert <meta name="KEYWORDS" content="libstdc++, libstdc++-v3, GCC, g++" /> 10*404b540aSrobert <meta name="DESCRIPTION" content="Configuration options for libstdc++-v3." /> 11*404b540aSrobert <meta name="GENERATOR" content="vi and eight fingers" /> 12*404b540aSrobert <title>libstdc++-v3 configure options</title> 13*404b540aSrobert<link rel="StyleSheet" href="lib3styles.css" type="text/css" /> 14*404b540aSrobert<link rel="Copyright" href="17_intro/license.html" type="text/html" /> 15*404b540aSrobert</head> 16*404b540aSrobert<body> 17*404b540aSrobert 18*404b540aSrobert<h1 class="centered"><a name="top">Interesting <code>configure</code> 19*404b540aSrobertoptions</a></h1> 20*404b540aSrobert 21*404b540aSrobert<p class="fineprint"><em> 22*404b540aSrobert The latest version of this document is always available at 23*404b540aSrobert <a href="http://gcc.gnu.org/onlinedocs/libstdc++/configopts.html"> 24*404b540aSrobert http://gcc.gnu.org/onlinedocs/libstdc++/configopts.html</a>. 25*404b540aSrobert</em></p> 26*404b540aSrobert 27*404b540aSrobert<p><em> 28*404b540aSrobert To the <a href="http://gcc.gnu.org/libstdc++/">libstdc++-v3 homepage</a>. 29*404b540aSrobert</em></p> 30*404b540aSrobert 31*404b540aSrobert<!-- ####################################################### --> 32*404b540aSrobert<hr /> 33*404b540aSrobert<p>Here are some of the non-obvious options to libstdc++'s configure. 34*404b540aSrobert Keep in mind that 35*404b540aSrobert <!-- This SECnn should be the "Choosing Package Options" section. --> 36*404b540aSrobert <a href="http://www.gnu.org/software/autoconf/manual/autoconf-2.57/html_node/autoconf_131.html#SEC131">they 37*404b540aSrobert all have opposite forms as well</a> 38*404b540aSrobert (enable/disable and with/without). The defaults are for <strong>current 39*404b540aSrobert development sources</strong>, which may be different than those for 40*404b540aSrobert released versions. 41*404b540aSrobert</p> 42*404b540aSrobert<p>The canonical way to find out the configure options that are 43*404b540aSrobert available for a given set of libstdc++ sources is to go to the 44*404b540aSrobert source directory and then type:<code> ./configure --help</code> 45*404b540aSrobert</p> 46*404b540aSrobert 47*404b540aSrobert<dl> 48*404b540aSrobert <dt><code>--enable-multilib </code>[default]</dt> 49*404b540aSrobert <dd><p>This is part of the generic multilib support for building cross 50*404b540aSrobert compilers. As such, targets like "powerpc-elf" will have 51*404b540aSrobert libstdc++ built many different ways: "-msoft-float" 52*404b540aSrobert and not, etc. A different libstdc++ will be built for each of 53*404b540aSrobert the different multilib versions. This option is on by default. 54*404b540aSrobert </p> 55*404b540aSrobert </dd> 56*404b540aSrobert 57*404b540aSrobert <dt><code>--enable-sjlj-exceptions </code></dt> 58*404b540aSrobert <dd><p>Forces old, set-jump/long-jump exception handling model. If 59*404b540aSrobert at all possible, the new, frame unwinding exception handling routines 60*404b540aSrobert should be used instead, as they significantly reduce both 61*404b540aSrobert runtime memory usage and executable size. This option can 62*404b540aSrobert change the library ABI. 63*404b540aSrobert </p> 64*404b540aSrobert </dd> 65*404b540aSrobert 66*404b540aSrobert <dt><code>--enable-version-specific-runtime-libs </code></dt> 67*404b540aSrobert <dd><p>Specify that run-time libraries should be installed in the 68*404b540aSrobert compiler-specific subdirectory (i.e., 69*404b540aSrobert <code>${libdir}/gcc-lib/${target_alias}/${gcc_version}</code>) 70*404b540aSrobert instead of <code>${libdir}</code>. This option is useful if you 71*404b540aSrobert intend to use several versions of gcc in parallel. In addition, 72*404b540aSrobert libstdc++'s include files will be installed in 73*404b540aSrobert <code>${libdir}/gcc-lib/${target_alias}/${gcc_version}/include/g++</code>, 74*404b540aSrobert unless you also specify 75*404b540aSrobert <code>--with-gxx-include-dir=<em>dirname</em></code> during configuration. 76*404b540aSrobert </p> 77*404b540aSrobert </dd> 78*404b540aSrobert 79*404b540aSrobert <dt><code>--with-gxx-include-dir=<include-files dir></code></dt> 80*404b540aSrobert <dd><p>Adds support for named libstdc++ include directory. For instance, 81*404b540aSrobert the following puts all the libstdc++ headers into a directory 82*404b540aSrobert called "2.97-20001008" instead of the usual 83*404b540aSrobert "c++/(version)". 84*404b540aSrobert </p> 85*404b540aSrobert <pre> 86*404b540aSrobert --with-gxx-include-dir=/foo/H-x86-gcc-3-c-gxx-inc/include/2.97-20001008</pre> </dd> 87*404b540aSrobert 88*404b540aSrobert <dt><code>--enable-cstdio </code></dt> 89*404b540aSrobert <dd><p>This is an abbreviated form of <code>'--enable-cstdio=stdio'</code> 90*404b540aSrobert (described next). This option can change the library ABI. 91*404b540aSrobert </p> 92*404b540aSrobert </dd> 93*404b540aSrobert 94*404b540aSrobert <dt><code>--enable-cstdio=OPTION </code></dt> 95*404b540aSrobert <dd><p>Select a target-specific I/O package. At the moment, the only 96*404b540aSrobert choice is to use 'stdio', a generic "C" abstraction. 97*404b540aSrobert The default is 'stdio'. A longer explanation is <a 98*404b540aSrobert href="explanations.html#cstdio">here</a>. 99*404b540aSrobert </p> 100*404b540aSrobert </dd> 101*404b540aSrobert 102*404b540aSrobert <dt><code>--enable-clocale </code></dt> 103*404b540aSrobert <dd><p>This is an abbreviated form of <code>'--enable-clocale=generic'</code> 104*404b540aSrobert (described next). This option can change the library ABI. 105*404b540aSrobert </p> 106*404b540aSrobert </dd> 107*404b540aSrobert 108*404b540aSrobert <dt><code>--enable-clocale=OPTION </code></dt> 109*404b540aSrobert <dd><p>Select a target-specific underlying locale package. The 110*404b540aSrobert choices are 'ieee_1003.1-2001' to specify an X/Open, Standard Unix 111*404b540aSrobert (IEEE Std. 1003.1-2001) model based on langinfo/iconv/catgets, 112*404b540aSrobert 'gnu' to specify a model based on functionality from the GNU C 113*404b540aSrobert library (langinfo/iconv/gettext) (from <a 114*404b540aSrobert href="http://sources.redhat.com/glibc/">glibc</a>, the GNU C 115*404b540aSrobert library), or 'generic' to use a generic "C" 116*404b540aSrobert abstraction which consists of "C" locale info. 117*404b540aSrobert </p> 118*404b540aSrobert 119*404b540aSrobert <p>As part of the configuration process, the "C" library is 120*404b540aSrobert probed both for sufficient vintage, and installed locale 121*404b540aSrobert data. If either of these elements are not present, the C++ 122*404b540aSrobert locale model default to 'generic.' On glibc-based systems of 123*404b540aSrobert version 2.2.5 and above with installed locale files, 'gnu' is 124*404b540aSrobert automatically selected. 125*404b540aSrobert </p> 126*404b540aSrobert </dd> 127*404b540aSrobert 128*404b540aSrobert <dt><code>--enable-libstdcxx-allocator </code></dt> 129*404b540aSrobert <dd><p>This is an abbreviated form of 130*404b540aSrobert <code>'--enable-libstdcxx-allocator=auto'</code> (described 131*404b540aSrobert next). This option can change the library ABI. 132*404b540aSrobert </p> 133*404b540aSrobert </dd> 134*404b540aSrobert 135*404b540aSrobert <dt><code>--enable-libstdcxx-allocator=OPTION </code></dt> 136*404b540aSrobert <dd><p>Select a target-specific underlying std::allocator. The 137*404b540aSrobert choices are 'new' to specify a wrapper for new, 'malloc' to 138*404b540aSrobert specify a wrapper for malloc, 'mt' for a fixed power of two allocator 139*404b540aSrobert (<a href="ext/mt_allocator.html">documented</a> under extensions), 140*404b540aSrobert 'pool' for the SGI pooled allocator or 'bitmap' for a bitmap allocator. 141*404b540aSrobert This option can change the library ABI. 142*404b540aSrobert </p> 143*404b540aSrobert </dd> 144*404b540aSrobert 145*404b540aSrobert <dt><code>--enable-cheaders=OPTION </code></dt> 146*404b540aSrobert <dd><p>This allows the user to define what kind of C headers are 147*404b540aSrobert used. Options are c and c_std. These correspond to the source 148*404b540aSrobert directory's include/c and include/c_std. The default is c_std. 149*404b540aSrobert </p> 150*404b540aSrobert </dd> 151*404b540aSrobert 152*404b540aSrobert <dt><code>--enable-threads </code></dt> 153*404b540aSrobert <dd><p>This is an abbreviated form of <code>'--enable-threads=yes'</code> 154*404b540aSrobert (described next). This option can change the library ABI. 155*404b540aSrobert </p> 156*404b540aSrobert </dd> 157*404b540aSrobert 158*404b540aSrobert <dt><code>--enable-threads=OPTION </code></dt> 159*404b540aSrobert <dd><p>Select a threading library. A full description is given in the 160*404b540aSrobert general <a href="http://gcc.gnu.org/install/configure.html">compiler 161*404b540aSrobert configuration instructions</a>. 162*404b540aSrobert </p> 163*404b540aSrobert </dd> 164*404b540aSrobert 165*404b540aSrobert <dt><code>--enable-libstdcxx-debug </code></dt> 166*404b540aSrobert <dd><p>Build separate debug libraries in addition to what is normally built. 167*404b540aSrobert By default, the debug libraries are compiled with 168*404b540aSrobert <code> CXXFLAGS='-g3 -O0'</code> 169*404b540aSrobert , are installed in <code>${libdir}/debug</code>, and have the 170*404b540aSrobert same names and versioning information as the non-debug 171*404b540aSrobert libraries. This option is off by default. 172*404b540aSrobert </p> 173*404b540aSrobert <p>Note this make command, executed in 174*404b540aSrobert the build directory, will do much the same thing, without the 175*404b540aSrobert configuration difference and without building everything twice: 176*404b540aSrobert <code>make CXXFLAGS='-g3 -O0' all</code> 177*404b540aSrobert </p> 178*404b540aSrobert </dd> 179*404b540aSrobert 180*404b540aSrobert <dt><code>--enable-libstdcxx-debug-flags=FLAGS</code></dt> 181*404b540aSrobert 182*404b540aSrobert <dd><p>This option is only valid when <code> --enable-debug </code> 183*404b540aSrobert is also specified, and applies to the debug builds only. With 184*404b540aSrobert this option, you can pass a specific string of flags to the 185*404b540aSrobert compiler to use when building the debug versions of libstdc++. 186*404b540aSrobert FLAGS is a quoted string of options, like 187*404b540aSrobert </p> 188*404b540aSrobert <pre> 189*404b540aSrobert --enable-libstdcxx-debug-flags='-g3 -O1 -gdwarf-2'</pre> 190*404b540aSrobert </dd> 191*404b540aSrobert 192*404b540aSrobert <dt><code>--enable-cxx-flags=FLAGS</code></dt> 193*404b540aSrobert <dd><p>With this option, you can pass a string of -f (functionality) 194*404b540aSrobert flags to the compiler to use when building libstdc++. This 195*404b540aSrobert option can change the library ABI. FLAGS is a quoted string of 196*404b540aSrobert options, like 197*404b540aSrobert </p> 198*404b540aSrobert <pre> 199*404b540aSrobert --enable-cxx-flags='-fvtable-gc -fomit-frame-pointer -ansi'</pre> 200*404b540aSrobert <p> 201*404b540aSrobert Note that the flags don't necessarily have to all be -f flags, 202*404b540aSrobert as shown, but usually those are the ones that will make sense 203*404b540aSrobert for experimentation and configure-time overriding. 204*404b540aSrobert </p> 205*404b540aSrobert <p>The advantage of --enable-cxx-flags over setting CXXFLAGS in 206*404b540aSrobert the 'make' environment is that, if files are automatically 207*404b540aSrobert rebuilt, the same flags will be used when compiling those files 208*404b540aSrobert as well, so that everything matches. 209*404b540aSrobert </p> 210*404b540aSrobert <p>Fun flags to try might include combinations of 211*404b540aSrobert </p> 212*404b540aSrobert <pre> 213*404b540aSrobert -fstrict-aliasing 214*404b540aSrobert -fno-exceptions 215*404b540aSrobert -ffunction-sections 216*404b540aSrobert -fvtable-gc</pre> 217*404b540aSrobert <p>and opposite forms (-fno-) of the same. Tell us (the libstdc++ 218*404b540aSrobert mailing list) if you discover more! 219*404b540aSrobert </p> 220*404b540aSrobert </dd> 221*404b540aSrobert 222*404b540aSrobert <dt><code>--enable-c99 </code></dt> 223*404b540aSrobert <dd><p>The "long long" type was introduced in C99, along 224*404b540aSrobert with many other functions for wide characters, and math 225*404b540aSrobert classification macros, etc. If enabled, all C99 functions not 226*404b540aSrobert specified by the C++ standard will be put into <code>namespace 227*404b540aSrobert __gnu_cxx</code>, and then all these names will 228*404b540aSrobert be injected into namespace std, so that C99 functions can be 229*404b540aSrobert used "as if" they were in the C++ standard (as they 230*404b540aSrobert will eventually be in some future revision of the standard, 231*404b540aSrobert without a doubt). By default, C99 support is on, assuming the 232*404b540aSrobert configure probes find all the necessary functions and bits 233*404b540aSrobert necessary. This option can change the library ABI. 234*404b540aSrobert </p> 235*404b540aSrobert </dd> 236*404b540aSrobert 237*404b540aSrobert <dt><code>--enable-wchar_t </code>[default]</dt> 238*404b540aSrobert <dd><p>Template specializations for the "wchar_t" type are 239*404b540aSrobert required for wide character conversion support. Disabling 240*404b540aSrobert wide character specializations may be expedient for initial 241*404b540aSrobert porting efforts, but builds only a subset of what is required by 242*404b540aSrobert ISO, and is not recommended. By default, this option is on. 243*404b540aSrobert This option can change the library ABI. 244*404b540aSrobert </p> 245*404b540aSrobert </dd> 246*404b540aSrobert 247*404b540aSrobert <dt><code>--enable-long-long </code></dt> 248*404b540aSrobert <dd><p>The "long long" type was introduced in C99. It is 249*404b540aSrobert provided as a GNU extension to C++98 in g++. This flag builds 250*404b540aSrobert support for "long long" into the library (specialized 251*404b540aSrobert templates and the like for iostreams). This option is on by default: 252*404b540aSrobert if enabled, users will have to either use the new-style "C" 253*404b540aSrobert headers by default (i.e., <cmath> not <math.h>) 254*404b540aSrobert or add appropriate compile-time flags to all compile lines to 255*404b540aSrobert allow "C" visibility of this feature (on GNU/Linux, 256*404b540aSrobert the flag is -D_ISOC99_SOURCE, which is added automatically via 257*404b540aSrobert CPLUSPLUS_CPP_SPEC's addition of _GNU_SOURCE). 258*404b540aSrobert This option can change the library ABI. 259*404b540aSrobert </p> 260*404b540aSrobert </dd> 261*404b540aSrobert 262*404b540aSrobert <dt><code>--enable-fully-dynamic-string </code></dt> 263*404b540aSrobert <dd><p>This option enables a special version of basic_string avoiding 264*404b540aSrobert the optimization that allocates empty objects in static memory. 265*404b540aSrobert Mostly useful together with shared memory allocators, see PR 266*404b540aSrobert libstdc++/16612 for details. 267*404b540aSrobert </p> 268*404b540aSrobert </dd> 269*404b540aSrobert 270*404b540aSrobert <dt><code>--enable-concept-checks </code></dt> 271*404b540aSrobert <dd><p>This turns on additional compile-time checks for instantiated 272*404b540aSrobert library templates, in the form of specialized templates, 273*404b540aSrobert <a href="19_diagnostics/howto.html#3">described here</a>. They 274*404b540aSrobert can help users discover when they break the rules of the STL, before 275*404b540aSrobert their programs run. 276*404b540aSrobert </p> 277*404b540aSrobert </dd> 278*404b540aSrobert 279*404b540aSrobert <dt><code>--enable-symvers[=style] </code></dt> 280*404b540aSrobert 281*404b540aSrobert <dd><p>In 3.1 and later, tries to turn on symbol versioning in the 282*404b540aSrobert shared library (if a shared library has been 283*404b540aSrobert requested). Values for 'style' that are currently supported 284*404b540aSrobert are 'gnu', 'gnu-versioned-namespace', 'darwin', and 285*404b540aSrobert 'darwin-export'. Both gnu- options require that a recent 286*404b540aSrobert version of the GNU linker be in use. Both darwin options are 287*404b540aSrobert equivalent. With no style given, the configure script will try 288*404b540aSrobert to guess correct defaults for the host system, probe to see if 289*404b540aSrobert additional requirements are necessary and present for 290*404b540aSrobert activation, and if so, will turn symbol versioning on. This 291*404b540aSrobert option can change the library ABI. 292*404b540aSrobert </p> 293*404b540aSrobert 294*404b540aSrobert </dd> 295*404b540aSrobert 296*404b540aSrobert <dt><code>--enable-visibility </code></dt> 297*404b540aSrobert <dd><p> In 4.2 and later, enables or disables visibility attributes. 298*404b540aSrobert If enabled (as by default), and the compiler seems capable of 299*404b540aSrobert passing the simple sanity checks thrown at it, adjusts items 300*404b540aSrobert in namespace std, namespace std::tr1, and namespace __gnu_cxx 301*404b540aSrobert so that -fvisibility options work. 302*404b540aSrobert </p> 303*404b540aSrobert </dd> 304*404b540aSrobert 305*404b540aSrobert <dt><code>--enable-libstdcxx-pch </code></dt> 306*404b540aSrobert <dd><p>In 3.4 and later, tries to turn on the generation of 307*404b540aSrobert stdc++.h.gch, a pre-compiled file including all the standard 308*404b540aSrobert C++ includes. If enabled (as by default), and the compiler 309*404b540aSrobert seems capable of passing the simple sanity checks thrown at 310*404b540aSrobert it, try to build stdc++.h.gch as part of the make process. 311*404b540aSrobert In addition, this generated file is used later on (by appending <code> 312*404b540aSrobert --include bits/stdc++.h </code> to CXXFLAGS) when running the 313*404b540aSrobert testsuite. 314*404b540aSrobert </p> 315*404b540aSrobert </dd> 316*404b540aSrobert 317*404b540aSrobert <dt><code>--disable-hosted-libstdcxx </code></dt> 318*404b540aSrobert <dd><p>By default, a complete <em>hosted</em> C++ library is built. The 319*404b540aSrobert C++ Standard also describes a <em>freestanding</em> environment, 320*404b540aSrobert in which only a minimal set of headers are provided. This option 321*404b540aSrobert builds such an environment. 322*404b540aSrobert </p> 323*404b540aSrobert </dd> 324*404b540aSrobert</dl> 325*404b540aSrobert<p>Return <a href="#top">to the top of the page</a> or 326*404b540aSrobert <a href="http://gcc.gnu.org/libstdc++/">to the libstdc++ homepage</a>. 327*404b540aSrobert</p> 328*404b540aSrobert 329*404b540aSrobert 330*404b540aSrobert<!-- ####################################################### --> 331*404b540aSrobert 332*404b540aSrobert<hr /> 333*404b540aSrobert<p class="fineprint"><em> 334*404b540aSrobertSee <a href="17_intro/license.html">license.html</a> for copying conditions. 335*404b540aSrobertComments and suggestions are welcome, and may be sent to 336*404b540aSrobert<a href="mailto:libstdc++@gcc.gnu.org">the libstdc++ mailing list</a>. 337*404b540aSrobert</em></p> 338*404b540aSrobert 339*404b540aSrobert 340*404b540aSrobert</body> 341*404b540aSrobert</html> 342