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1<html lang="en"> 2<head> 3<title>Installing GCC: Configuration</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Installing GCC: Configuration"> 6<meta name="generator" content="makeinfo 4.13"> 7<link title="Top" rel="top" href="#Top"> 8<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 9<!-- 10Copyright (C) 1988-2017 Free Software Foundation, Inc. 11 12 Permission is granted to copy, distribute and/or modify this document 13under the terms of the GNU Free Documentation License, Version 1.3 or 14any later version published by the Free Software Foundation; with no 15Invariant Sections, the Front-Cover texts being (a) (see below), and 16with the Back-Cover Texts being (b) (see below). A copy of the 17license is included in the section entitled "GNU Free Documentation License". 18 19(a) The FSF's Front-Cover Text is: 20 21 A GNU Manual 22 23(b) The FSF's Back-Cover Text is: 24 25 You have freedom to copy and modify this GNU Manual, like GNU 26 software. Copies published by the Free Software Foundation raise 27 funds for GNU development.--> 28<meta http-equiv="Content-Style-Type" content="text/css"> 29<style type="text/css"><!-- 30 pre.display { font-family:inherit } 31 pre.format { font-family:inherit } 32 pre.smalldisplay { font-family:inherit; font-size:smaller } 33 pre.smallformat { font-family:inherit; font-size:smaller } 34 pre.smallexample { font-size:smaller } 35 pre.smalllisp { font-size:smaller } 36 span.sc { font-variant:small-caps } 37 span.roman { font-family:serif; font-weight:normal; } 38 span.sansserif { font-family:sans-serif; font-weight:normal; } 39--></style> 40</head> 41<body> 42<h1 class="settitle">Installing GCC: Configuration</h1> 43<a name="index-Configuration-1"></a><a name="index-Installing-GCC_003a-Configuration-2"></a> 44Like most GNU software, GCC must be configured before it can be built. 45This document describes the recommended configuration procedure 46for both native and cross targets. 47 48 <p>We use <var>srcdir</var> to refer to the toplevel source directory for 49GCC; we use <var>objdir</var> to refer to the toplevel build/object directory. 50 51 <p>If you obtained the sources via SVN, <var>srcdir</var> must refer to the top 52<samp><span class="file">gcc</span></samp> directory, the one where the <samp><span class="file">MAINTAINERS</span></samp> file can be 53found, and not its <samp><span class="file">gcc</span></samp> subdirectory, otherwise the build will fail. 54 55 <p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS 56file system, the shell's built-in <samp><span class="command">pwd</span></samp> command will return 57temporary pathnames. Using these can lead to various sorts of build 58problems. To avoid this issue, set the <samp><span class="env">PWDCMD</span></samp> environment 59variable to an automounter-aware <samp><span class="command">pwd</span></samp> command, e.g., 60<samp><span class="command">pawd</span></samp> or ‘<samp><span class="samp">amq -w</span></samp>’, during the configuration and build 61phases. 62 63 <p>First, we <strong>highly</strong> recommend that GCC be built into a 64separate directory from the sources which does <strong>not</strong> reside 65within the source tree. This is how we generally build GCC; building 66where <var>srcdir</var> == <var>objdir</var> should still work, but doesn't 67get extensive testing; building where <var>objdir</var> is a subdirectory 68of <var>srcdir</var> is unsupported. 69 70 <p>If you have previously built GCC in the same directory for a 71different target machine, do ‘<samp><span class="samp">make distclean</span></samp>’ to delete all files 72that might be invalid. One of the files this deletes is <samp><span class="file">Makefile</span></samp>; 73if ‘<samp><span class="samp">make distclean</span></samp>’ complains that <samp><span class="file">Makefile</span></samp> does not exist 74or issues a message like “don't know how to make distclean” it probably 75means that the directory is already suitably clean. However, with the 76recommended method of building in a separate <var>objdir</var>, you should 77simply use a different <var>objdir</var> for each target. 78 79 <p>Second, when configuring a native system, either <samp><span class="command">cc</span></samp> or 80<samp><span class="command">gcc</span></samp> must be in your path or you must set <samp><span class="env">CC</span></samp> in 81your environment before running configure. Otherwise the configuration 82scripts may fail. 83 84 <p>To configure GCC: 85 86<pre class="smallexample"> % mkdir <var>objdir</var> 87 % cd <var>objdir</var> 88 % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>] 89</pre> 90 <h3 class="heading"><a name="TOC0"></a>Distributor options</h3> 91 92<p>If you will be distributing binary versions of GCC, with modifications 93to the source code, you should use the options described in this 94section to make clear that your version contains modifications. 95 96 <dl> 97<dt><code>--with-pkgversion=</code><var>version</var><dd>Specify a string that identifies your package. You may wish 98to include a build number or build date. This version string will be 99included in the output of <samp><span class="command">gcc --version</span></samp>. This suffix does 100not replace the default version string, only the ‘<samp><span class="samp">GCC</span></samp>’ part. 101 102 <p>The default value is ‘<samp><span class="samp">GCC</span></samp>’. 103 104 <br><dt><code>--with-bugurl=</code><var>url</var><dd>Specify the URL that users should visit if they wish to report a bug. 105You are of course welcome to forward bugs reported to you to the FSF, 106if you determine that they are not bugs in your modifications. 107 108 <p>The default value refers to the FSF's GCC bug tracker. 109 110 </dl> 111 112<h3 class="heading"><a name="TOC1"></a>Target specification</h3> 113 114 <ul> 115<li>GCC has code to correctly determine the correct value for <var>target</var> 116for nearly all native systems. Therefore, we highly recommend you do 117not provide a configure target when configuring a native compiler. 118 119 <li><var>target</var> must be specified as <samp><span class="option">--target=</span><var>target</var></samp> 120when configuring a cross compiler; examples of valid targets would be 121m68k-elf, sh-elf, etc. 122 123 <li>Specifying just <var>target</var> instead of <samp><span class="option">--target=</span><var>target</var></samp> 124implies that the host defaults to <var>target</var>. 125</ul> 126 127<h3 class="heading"><a name="TOC2"></a>Options specification</h3> 128 129<p>Use <var>options</var> to override several configure time options for 130GCC. A list of supported <var>options</var> follows; ‘<samp><span class="samp">configure 131--help</span></samp>’ may list other options, but those not listed below may not 132work and should not normally be used. 133 134 <p>Note that each <samp><span class="option">--enable</span></samp> option has a corresponding 135<samp><span class="option">--disable</span></samp> option and that each <samp><span class="option">--with</span></samp> option has a 136corresponding <samp><span class="option">--without</span></samp> option. 137 138 <dl> 139<dt><code>--prefix=</code><var>dirname</var><dd>Specify the toplevel installation 140directory. This is the recommended way to install the tools into a directory 141other than the default. The toplevel installation directory defaults to 142<samp><span class="file">/usr/local</span></samp>. 143 144 <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a 145subdirectory of <var>objdir</var> or vice versa. If specifying a directory 146beneath a user's home directory tree, some shells will not expand 147<var>dirname</var> correctly if it contains the ‘<samp><span class="samp">~</span></samp>’ metacharacter; use 148<samp><span class="env">$HOME</span></samp> instead. 149 150 <p>The following standard <samp><span class="command">autoconf</span></samp> options are supported. Normally you 151should not need to use these options. 152 <dl> 153<dt><code>--exec-prefix=</code><var>dirname</var><dd>Specify the toplevel installation directory for architecture-dependent 154files. The default is <samp><var>prefix</var></samp>. 155 156 <br><dt><code>--bindir=</code><var>dirname</var><dd>Specify the installation directory for the executables called by users 157(such as <samp><span class="command">gcc</span></samp> and <samp><span class="command">g++</span></samp>). The default is 158<samp><var>exec-prefix</var><span class="file">/bin</span></samp>. 159 160 <br><dt><code>--libdir=</code><var>dirname</var><dd>Specify the installation directory for object code libraries and 161internal data files of GCC. The default is <samp><var>exec-prefix</var><span class="file">/lib</span></samp>. 162 163 <br><dt><code>--libexecdir=</code><var>dirname</var><dd>Specify the installation directory for internal executables of GCC. 164The default is <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>. 165 166 <br><dt><code>--with-slibdir=</code><var>dirname</var><dd>Specify the installation directory for the shared libgcc library. The 167default is <samp><var>libdir</var></samp>. 168 169 <br><dt><code>--datarootdir=</code><var>dirname</var><dd>Specify the root of the directory tree for read-only architecture-independent 170data files referenced by GCC. The default is <samp><var>prefix</var><span class="file">/share</span></samp>. 171 172 <br><dt><code>--infodir=</code><var>dirname</var><dd>Specify the installation directory for documentation in info format. 173The default is <samp><var>datarootdir</var><span class="file">/info</span></samp>. 174 175 <br><dt><code>--datadir=</code><var>dirname</var><dd>Specify the installation directory for some architecture-independent 176data files referenced by GCC. The default is <samp><var>datarootdir</var></samp>. 177 178 <br><dt><code>--docdir=</code><var>dirname</var><dd>Specify the installation directory for documentation files (other 179than Info) for GCC. The default is <samp><var>datarootdir</var><span class="file">/doc</span></samp>. 180 181 <br><dt><code>--htmldir=</code><var>dirname</var><dd>Specify the installation directory for HTML documentation files. 182The default is <samp><var>docdir</var></samp>. 183 184 <br><dt><code>--pdfdir=</code><var>dirname</var><dd>Specify the installation directory for PDF documentation files. 185The default is <samp><var>docdir</var></samp>. 186 187 <br><dt><code>--mandir=</code><var>dirname</var><dd>Specify the installation directory for manual pages. The default is 188<samp><var>datarootdir</var><span class="file">/man</span></samp>. (Note that the manual pages are only extracts 189from the full GCC manuals, which are provided in Texinfo format. The manpages 190are derived by an automatic conversion process from parts of the full 191manual.) 192 193 <br><dt><code>--with-gxx-include-dir=</code><var>dirname</var><dd>Specify 194the installation directory for G++ header files. The default depends 195on other configuration options, and differs between cross and native 196configurations. 197 198 <br><dt><code>--with-specs=</code><var>specs</var><dd>Specify additional command line driver SPECS. 199This can be useful if you need to turn on a non-standard feature by 200default without modifying the compiler's source code, for instance 201<samp><span class="option">--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</span></samp>. 202See “Spec Files” in the main manual 203 204 </dl> 205 206 <br><dt><code>--program-prefix=</code><var>prefix</var><dd>GCC supports some transformations of the names of its programs when 207installing them. This option prepends <var>prefix</var> to the names of 208programs to install in <var>bindir</var> (see above). For example, specifying 209<samp><span class="option">--program-prefix=foo-</span></samp> would result in ‘<samp><span class="samp">gcc</span></samp>’ 210being installed as <samp><span class="file">/usr/local/bin/foo-gcc</span></samp>. 211 212 <br><dt><code>--program-suffix=</code><var>suffix</var><dd>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var> 213(see above). For example, specifying <samp><span class="option">--program-suffix=-3.1</span></samp> 214would result in ‘<samp><span class="samp">gcc</span></samp>’ being installed as 215<samp><span class="file">/usr/local/bin/gcc-3.1</span></samp>. 216 217 <br><dt><code>--program-transform-name=</code><var>pattern</var><dd>Applies the ‘<samp><span class="samp">sed</span></samp>’ script <var>pattern</var> to be applied to the names 218of programs to install in <var>bindir</var> (see above). <var>pattern</var> has to 219consist of one or more basic ‘<samp><span class="samp">sed</span></samp>’ editing commands, separated by 220semicolons. For example, if you want the ‘<samp><span class="samp">gcc</span></samp>’ program name to be 221transformed to the installed program <samp><span class="file">/usr/local/bin/myowngcc</span></samp> and 222the ‘<samp><span class="samp">g++</span></samp>’ program name to be transformed to 223<samp><span class="file">/usr/local/bin/gspecial++</span></samp> without changing other program names, 224you could use the pattern 225<samp><span class="option">--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</span></samp> 226to achieve this effect. 227 228 <p>All three options can be combined and used together, resulting in more 229complex conversion patterns. As a basic rule, <var>prefix</var> (and 230<var>suffix</var>) are prepended (appended) before further transformations 231can happen with a special transformation script <var>pattern</var>. 232 233 <p>As currently implemented, this option only takes effect for native 234builds; cross compiler binaries' names are not transformed even when a 235transformation is explicitly asked for by one of these options. 236 237 <p>For native builds, some of the installed programs are also installed 238with the target alias in front of their name, as in 239‘<samp><span class="samp">i686-pc-linux-gnu-gcc</span></samp>’. All of the above transformations happen 240before the target alias is prepended to the name—so, specifying 241<samp><span class="option">--program-prefix=foo-</span></samp> and <samp><span class="option">program-suffix=-3.1</span></samp>, the 242resulting binary would be installed as 243<samp><span class="file">/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</span></samp>. 244 245 <p>As a last shortcoming, none of the installed Ada programs are 246transformed yet, which will be fixed in some time. 247 248 <br><dt><code>--with-local-prefix=</code><var>dirname</var><dd>Specify the 249installation directory for local include files. The default is 250<samp><span class="file">/usr/local</span></samp>. Specify this option if you want the compiler to 251search directory <samp><var>dirname</var><span class="file">/include</span></samp> for locally installed 252header files <em>instead</em> of <samp><span class="file">/usr/local/include</span></samp>. 253 254 <p>You should specify <samp><span class="option">--with-local-prefix</span></samp> <strong>only</strong> if your 255site has a different convention (not <samp><span class="file">/usr/local</span></samp>) for where to put 256site-specific files. 257 258 <p>The default value for <samp><span class="option">--with-local-prefix</span></samp> is <samp><span class="file">/usr/local</span></samp> 259regardless of the value of <samp><span class="option">--prefix</span></samp>. Specifying 260<samp><span class="option">--prefix</span></samp> has no effect on which directory GCC searches for 261local header files. This may seem counterintuitive, but actually it is 262logical. 263 264 <p>The purpose of <samp><span class="option">--prefix</span></samp> is to specify where to <em>install 265GCC</em>. The local header files in <samp><span class="file">/usr/local/include</span></samp>—if you put 266any in that directory—are not part of GCC. They are part of other 267programs—perhaps many others. (GCC installs its own header files in 268another directory which is based on the <samp><span class="option">--prefix</span></samp> value.) 269 270 <p>Both the local-prefix include directory and the GCC-prefix include 271directory are part of GCC's “system include” directories. Although these 272two directories are not fixed, they need to be searched in the proper 273order for the correct processing of the include_next directive. The 274local-prefix include directory is searched before the GCC-prefix 275include directory. Another characteristic of system include directories 276is that pedantic warnings are turned off for headers in these directories. 277 278 <p>Some autoconf macros add <samp><span class="option">-I </span><var>directory</var></samp> options to the 279compiler command line, to ensure that directories containing installed 280packages' headers are searched. When <var>directory</var> is one of GCC's 281system include directories, GCC will ignore the option so that system 282directories continue to be processed in the correct order. This 283may result in a search order different from what was specified but the 284directory will still be searched. 285 286 <p>GCC automatically searches for ordinary libraries using 287<samp><span class="env">GCC_EXEC_PREFIX</span></samp>. Thus, when the same installation prefix is 288used for both GCC and packages, GCC will automatically search for 289both headers and libraries. This provides a configuration that is 290easy to use. GCC behaves in a manner similar to that when it is 291installed as a system compiler in <samp><span class="file">/usr</span></samp>. 292 293 <p>Sites that need to install multiple versions of GCC may not want to 294use the above simple configuration. It is possible to use the 295<samp><span class="option">--program-prefix</span></samp>, <samp><span class="option">--program-suffix</span></samp> and 296<samp><span class="option">--program-transform-name</span></samp> options to install multiple versions 297into a single directory, but it may be simpler to use different prefixes 298and the <samp><span class="option">--with-local-prefix</span></samp> option to specify the location of the 299site-specific files for each version. It will then be necessary for 300users to specify explicitly the location of local site libraries 301(e.g., with <samp><span class="env">LIBRARY_PATH</span></samp>). 302 303 <p>The same value can be used for both <samp><span class="option">--with-local-prefix</span></samp> and 304<samp><span class="option">--prefix</span></samp> provided it is not <samp><span class="file">/usr</span></samp>. This can be used 305to avoid the default search of <samp><span class="file">/usr/local/include</span></samp>. 306 307 <p><strong>Do not</strong> specify <samp><span class="file">/usr</span></samp> as the <samp><span class="option">--with-local-prefix</span></samp>! 308The directory you use for <samp><span class="option">--with-local-prefix</span></samp> <strong>must not</strong> 309contain any of the system's standard header files. If it did contain 310them, certain programs would be miscompiled (including GNU Emacs, on 311certain targets), because this would override and nullify the header 312file corrections made by the <samp><span class="command">fixincludes</span></samp> script. 313 314 <p>Indications are that people who use this option use it based on mistaken 315ideas of what it is for. People use it as if it specified where to 316install part of GCC. Perhaps they make this assumption because 317installing GCC creates the directory. 318 319 <br><dt><code>--with-native-system-header-dir=</code><var>dirname</var><dd>Specifies that <var>dirname</var> is the directory that contains native system 320header files, rather than <samp><span class="file">/usr/include</span></samp>. This option is most useful 321if you are creating a compiler that should be isolated from the system 322as much as possible. It is most commonly used with the 323<samp><span class="option">--with-sysroot</span></samp> option and will cause GCC to search 324<var>dirname</var> inside the system root specified by that option. 325 326 <br><dt><code>--enable-shared[=</code><var>package</var><code>[,...]]</code><dd>Build shared versions of libraries, if shared libraries are supported on 327the target platform. Unlike GCC 2.95.x and earlier, shared libraries 328are enabled by default on all platforms that support shared libraries. 329 330 <p>If a list of packages is given as an argument, build shared libraries 331only for the listed packages. For other packages, only static libraries 332will be built. Package names currently recognized in the GCC tree are 333‘<samp><span class="samp">libgcc</span></samp>’ (also known as ‘<samp><span class="samp">gcc</span></samp>’), ‘<samp><span class="samp">libstdc++</span></samp>’ (not 334‘<samp><span class="samp">libstdc++-v3</span></samp>’), ‘<samp><span class="samp">libffi</span></samp>’, ‘<samp><span class="samp">zlib</span></samp>’, ‘<samp><span class="samp">boehm-gc</span></samp>’, 335‘<samp><span class="samp">ada</span></samp>’, ‘<samp><span class="samp">libada</span></samp>’, ‘<samp><span class="samp">libjava</span></samp>’, ‘<samp><span class="samp">libgo</span></samp>’, and ‘<samp><span class="samp">libobjc</span></samp>’. 336Note ‘<samp><span class="samp">libiberty</span></samp>’ does not support shared libraries at all. 337 338 <p>Use <samp><span class="option">--disable-shared</span></samp> to build only static libraries. Note that 339<samp><span class="option">--disable-shared</span></samp> does not accept a list of package names as 340argument, only <samp><span class="option">--enable-shared</span></samp> does. 341 342 <p>Contrast with <samp><span class="option">--enable-host-shared</span></samp>, which affects <em>host</em> 343code. 344 345 <br><dt><code>--enable-host-shared</code><dd>Specify that the <em>host</em> code should be built into position-independent 346machine code (with -fPIC), allowing it to be used within shared libraries, 347but yielding a slightly slower compiler. 348 349 <p>This option is required when building the libgccjit.so library. 350 351 <p>Contrast with <samp><span class="option">--enable-shared</span></samp>, which affects <em>target</em> 352libraries. 353 354 <br><dt><code><a name="with_002dgnu_002das"></a>--with-gnu-as</code><dd>Specify that the compiler should assume that the 355assembler it finds is the GNU assembler. However, this does not modify 356the rules to find an assembler and will result in confusion if the 357assembler found is not actually the GNU assembler. (Confusion may also 358result if the compiler finds the GNU assembler but has not been 359configured with <samp><span class="option">--with-gnu-as</span></samp>.) If you have more than one 360assembler installed on your system, you may want to use this option in 361connection with <samp><span class="option">--with-as=</span><var>pathname</var></samp> or 362<samp><span class="option">--with-build-time-tools=</span><var>pathname</var></samp>. 363 364 <p>The following systems are the only ones where it makes a difference 365whether you use the GNU assembler. On any other system, 366<samp><span class="option">--with-gnu-as</span></samp> has no effect. 367 368 <ul> 369<li>‘<samp><span class="samp">hppa1.0-</span><var>any</var><span class="samp">-</span><var>any</var></samp>’ 370<li>‘<samp><span class="samp">hppa1.1-</span><var>any</var><span class="samp">-</span><var>any</var></samp>’ 371<li>‘<samp><span class="samp">sparc-sun-solaris2.</span><var>any</var></samp>’ 372<li>‘<samp><span class="samp">sparc64-</span><var>any</var><span class="samp">-solaris2.</span><var>any</var></samp>’ 373</ul> 374 375 <br><dt><code><a name="with_002das"></a>--with-as=</code><var>pathname</var><dd>Specify that the compiler should use the assembler pointed to by 376<var>pathname</var>, rather than the one found by the standard rules to find 377an assembler, which are: 378 <ul> 379<li>Unless GCC is being built with a cross compiler, check the 380<samp><var>libexec</var><span class="file">/gcc/</span><var>target</var><span class="file">/</span><var>version</var></samp> directory. 381<var>libexec</var> defaults to <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>; 382<var>exec-prefix</var> defaults to <var>prefix</var>, which 383defaults to <samp><span class="file">/usr/local</span></samp> unless overridden by the 384<samp><span class="option">--prefix=</span><var>pathname</var></samp> switch described above. <var>target</var> 385is the target system triple, such as ‘<samp><span class="samp">sparc-sun-solaris2.7</span></samp>’, and 386<var>version</var> denotes the GCC version, such as 3.0. 387 388 <li>If the target system is the same that you are building on, check 389operating system specific directories (e.g. <samp><span class="file">/usr/ccs/bin</span></samp> on 390Sun Solaris 2). 391 392 <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is prefixed by the 393target system triple. 394 395 <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is not prefixed by the 396target system triple, if the host and target system triple are 397the same (in other words, we use a host tool if it can be used for 398the target as well). 399</ul> 400 401 <p>You may want to use <samp><span class="option">--with-as</span></samp> if no assembler 402is installed in the directories listed above, or if you have multiple 403assemblers installed and want to choose one that is not found by the 404above rules. 405 406 <br><dt><code><a name="with_002dgnu_002dld"></a>--with-gnu-ld</code><dd>Same as <a href="#with-gnu-as"><samp><span class="option">--with-gnu-as</span></samp></a> 407but for the linker. 408 409 <br><dt><code>--with-ld=</code><var>pathname</var><dd>Same as <a href="#with-as"><samp><span class="option">--with-as</span></samp></a> 410but for the linker. 411 412 <br><dt><code>--with-stabs</code><dd>Specify that stabs debugging 413information should be used instead of whatever format the host normally 414uses. Normally GCC uses the same debug format as the host system. 415 416 <p>On MIPS based systems and on Alphas, you must specify whether you want 417GCC to create the normal ECOFF debugging format, or to use BSD-style 418stabs passed through the ECOFF symbol table. The normal ECOFF debug 419format cannot fully handle languages other than C. BSD stabs format can 420handle other languages, but it only works with the GNU debugger GDB. 421 422 <p>Normally, GCC uses the ECOFF debugging format by default; if you 423prefer BSD stabs, specify <samp><span class="option">--with-stabs</span></samp> when you configure GCC. 424 425 <p>No matter which default you choose when you configure GCC, the user 426can use the <samp><span class="option">-gcoff</span></samp> and <samp><span class="option">-gstabs+</span></samp> options to specify explicitly 427the debug format for a particular compilation. 428 429 <p><samp><span class="option">--with-stabs</span></samp> is meaningful on the ISC system on the 386, also, if 430<samp><span class="option">--with-gas</span></samp> is used. It selects use of stabs debugging 431information embedded in COFF output. This kind of debugging information 432supports C++ well; ordinary COFF debugging information does not. 433 434 <p><samp><span class="option">--with-stabs</span></samp> is also meaningful on 386 systems running SVR4. It 435selects use of stabs debugging information embedded in ELF output. The 436C++ compiler currently (2.6.0) does not support the DWARF debugging 437information normally used on 386 SVR4 platforms; stabs provide a 438workable alternative. This requires gas and gdb, as the normal SVR4 439tools can not generate or interpret stabs. 440 441 <br><dt><code>--with-tls=</code><var>dialect</var><dd>Specify the default TLS dialect, for systems were there is a choice. 442For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or 443<code>gnu2</code>, which select between the original GNU dialect and the GNU TLS 444descriptor-based dialect. 445 446 <br><dt><code>--enable-multiarch</code><dd>Specify whether to enable or disable multiarch support. The default is 447to check for glibc start files in a multiarch location, and enable it 448if the files are found. The auto detection is enabled for native builds, 449and for cross builds configured with <samp><span class="option">--with-sysroot</span></samp>, and without 450<samp><span class="option">--with-native-system-header-dir</span></samp>. 451More documentation about multiarch can be found at 452<a href="https://wiki.debian.org/Multiarch">https://wiki.debian.org/Multiarch</a>. 453 454 <br><dt><code>--enable-sjlj-exceptions</code><dd>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. 455‘<samp><span class="samp">configure</span></samp>’ ordinarily picks the correct value based on the platform. 456Only use this option if you are sure you need a different setting. 457 458 <br><dt><code>--enable-vtable-verify</code><dd>Specify whether to enable or disable the vtable verification feature. 459Enabling this feature causes libstdc++ to be built with its virtual calls 460in verifiable mode. This means that, when linked with libvtv, every 461virtual call in libstdc++ will verify the vtable pointer through which the 462call will be made before actually making the call. If not linked with libvtv, 463the verifier will call stub functions (in libstdc++ itself) and do nothing. 464If vtable verification is disabled, then libstdc++ is not built with its 465virtual calls in verifiable mode at all. However the libvtv library will 466still be built (see <samp><span class="option">--disable-libvtv</span></samp> to turn off building libvtv). 467<samp><span class="option">--disable-vtable-verify</span></samp> is the default. 468 469 <br><dt><code>--disable-multilib</code><dd>Specify that multiple target 470libraries to support different target variants, calling 471conventions, etc. should not be built. The default is to build a 472predefined set of them. 473 474 <p>Some targets provide finer-grained control over which multilibs are built 475(e.g., <samp><span class="option">--disable-softfloat</span></samp>): 476 <dl> 477<dt><code>arm-*-*</code><dd>fpu, 26bit, underscore, interwork, biendian, nofmult. 478 479 <br><dt><code>m68*-*-*</code><dd>softfloat, m68881, m68000, m68020. 480 481 <br><dt><code>mips*-*-*</code><dd>single-float, biendian, softfloat. 482 483 <br><dt><code>powerpc*-*-*, rs6000*-*-*</code><dd>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian, 484sysv, aix. 485 486 </dl> 487 488 <br><dt><code>--with-multilib-list=</code><var>list</var><dt><code>--without-multilib-list</code><dd>Specify what multilibs to build. 489Currently only implemented for arm*-*-*, sh*-*-* and x86-64-*-linux*. 490 491 <dl> 492<dt><code>arm*-*-*</code><dd><var>list</var> is either <code>default</code> or <code>aprofile</code>. Specifying 493<code>default</code> is equivalent to omitting this option while specifying 494<code>aprofile</code> builds multilibs for each combination of ISA (<code>-marm</code> or 495<code>-mthumb</code>), architecture (<code>-march=armv7-a</code>, <code>-march=armv7ve</code>, 496or <code>-march=armv8-a</code>), FPU available (none, <code>-mfpu=vfpv3-d16</code>, 497<code>-mfpu=neon</code>, <code>-mfpu=vfpv4-d16</code>, <code>-mfpu=neon-vfpv4</code> or 498<code>-mfpu=neon-fp-armv8</code> depending on architecture) and floating-point ABI 499(<code>-mfloat-abi=softfp</code> or <code>-mfloat-abi=hard</code>). 500 501 <br><dt><code>sh*-*-*</code><dd><var>list</var> is a comma separated list of CPU names. These must be of the 502form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option 503for that processor). The list should not contain any endian options - 504these are handled by <samp><span class="option">--with-endian</span></samp>. 505 506 <p>If <var>list</var> is empty, then there will be no multilibs for extra 507processors. The multilib for the secondary endian remains enabled. 508 509 <p>As a special case, if an entry in the list starts with a <code>!</code> 510(exclamation point), then it is added to the list of excluded multilibs. 511Entries of this sort should be compatible with ‘<samp><span class="samp">MULTILIB_EXCLUDES</span></samp>’ 512(once the leading <code>!</code> has been stripped). 513 514 <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then a default set of 515multilibs is selected based on the value of <samp><span class="option">--target</span></samp>. This is 516usually the complete set of libraries, but some targets imply a more 517specialized subset. 518 519 <p>Example 1: to configure a compiler for SH4A only, but supporting both 520endians, with little endian being the default: 521 <pre class="smallexample"> --with-cpu=sh4a --with-endian=little,big --with-multilib-list= 522</pre> 523 <p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with 524only little endian SH4AL: 525 <pre class="smallexample"> --with-cpu=sh4a --with-endian=little,big \ 526 --with-multilib-list=sh4al,!mb/m4al 527</pre> 528 <br><dt><code>x86-64-*-linux*</code><dd><var>list</var> is a comma separated list of <code>m32</code>, <code>m64</code> and 529<code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries, 530respectively. If <var>list</var> is empty, then there will be no multilibs 531and only the default run-time library will be enabled. 532 533 <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then only 32-bit and 53464-bit run-time libraries will be enabled. 535</dl> 536 537 <br><dt><code>--with-endian=</code><var>endians</var><dd>Specify what endians to use. 538Currently only implemented for sh*-*-*. 539 540 <p><var>endians</var> may be one of the following: 541 <dl> 542<dt><code>big</code><dd>Use big endian exclusively. 543<br><dt><code>little</code><dd>Use little endian exclusively. 544<br><dt><code>big,little</code><dd>Use big endian by default. Provide a multilib for little endian. 545<br><dt><code>little,big</code><dd>Use little endian by default. Provide a multilib for big endian. 546</dl> 547 548 <br><dt><code>--enable-threads</code><dd>Specify that the target 549supports threads. This affects the Objective-C compiler and runtime 550library, and exception handling for other languages like C++ and Java. 551On some systems, this is the default. 552 553 <p>In general, the best (and, in many cases, the only known) threading 554model available will be configured for use. Beware that on some 555systems, GCC has not been taught what threading models are generally 556available for the system. In this case, <samp><span class="option">--enable-threads</span></samp> is an 557alias for <samp><span class="option">--enable-threads=single</span></samp>. 558 559 <br><dt><code>--disable-threads</code><dd>Specify that threading support should be disabled for the system. 560This is an alias for <samp><span class="option">--enable-threads=single</span></samp>. 561 562 <br><dt><code>--enable-threads=</code><var>lib</var><dd>Specify that 563<var>lib</var> is the thread support library. This affects the Objective-C 564compiler and runtime library, and exception handling for other languages 565like C++ and Java. The possibilities for <var>lib</var> are: 566 567 <dl> 568<dt><code>aix</code><dd>AIX thread support. 569<br><dt><code>dce</code><dd>DCE thread support. 570<br><dt><code>lynx</code><dd>LynxOS thread support. 571<br><dt><code>mipssde</code><dd>MIPS SDE thread support. 572<br><dt><code>no</code><dd>This is an alias for ‘<samp><span class="samp">single</span></samp>’. 573<br><dt><code>posix</code><dd>Generic POSIX/Unix98 thread support. 574<br><dt><code>rtems</code><dd>RTEMS thread support. 575<br><dt><code>single</code><dd>Disable thread support, should work for all platforms. 576<br><dt><code>tpf</code><dd>TPF thread support. 577<br><dt><code>vxworks</code><dd>VxWorks thread support. 578<br><dt><code>win32</code><dd>Microsoft Win32 API thread support. 579</dl> 580 581 <br><dt><code>--enable-tls</code><dd>Specify that the target supports TLS (Thread Local Storage). Usually 582configure can correctly determine if TLS is supported. In cases where 583it guesses incorrectly, TLS can be explicitly enabled or disabled with 584<samp><span class="option">--enable-tls</span></samp> or <samp><span class="option">--disable-tls</span></samp>. This can happen if 585the assembler supports TLS but the C library does not, or if the 586assumptions made by the configure test are incorrect. 587 588 <br><dt><code>--disable-tls</code><dd>Specify that the target does not support TLS. 589This is an alias for <samp><span class="option">--enable-tls=no</span></samp>. 590 591 <br><dt><code>--with-cpu=</code><var>cpu</var><dt><code>--with-cpu-32=</code><var>cpu</var><dt><code>--with-cpu-64=</code><var>cpu</var><dd>Specify which cpu variant the compiler should generate code for by default. 592<var>cpu</var> will be used as the default value of the <samp><span class="option">-mcpu=</span></samp> switch. 593This option is only supported on some targets, including ARC, ARM, i386, M68k, 594PowerPC, and SPARC. It is mandatory for ARC. The <samp><span class="option">--with-cpu-32</span></samp> and 595<samp><span class="option">--with-cpu-64</span></samp> options specify separate default CPUs for 59632-bit and 64-bit modes; these options are only supported for i386, 597x86-64, PowerPC, and SPARC. 598 599 <br><dt><code>--with-schedule=</code><var>cpu</var><dt><code>--with-arch=</code><var>cpu</var><dt><code>--with-arch-32=</code><var>cpu</var><dt><code>--with-arch-64=</code><var>cpu</var><dt><code>--with-tune=</code><var>cpu</var><dt><code>--with-tune-32=</code><var>cpu</var><dt><code>--with-tune-64=</code><var>cpu</var><dt><code>--with-abi=</code><var>abi</var><dt><code>--with-fpu=</code><var>type</var><dt><code>--with-float=</code><var>type</var><dd>These configure options provide default values for the <samp><span class="option">-mschedule=</span></samp>, 600<samp><span class="option">-march=</span></samp>, <samp><span class="option">-mtune=</span></samp>, <samp><span class="option">-mabi=</span></samp>, and <samp><span class="option">-mfpu=</span></samp> 601options and for <samp><span class="option">-mhard-float</span></samp> or <samp><span class="option">-msoft-float</span></samp>. As with 602<samp><span class="option">--with-cpu</span></samp>, which switches will be accepted and acceptable values 603of the arguments depend on the target. 604 605 <br><dt><code>--with-mode=</code><var>mode</var><dd>Specify if the compiler should default to <samp><span class="option">-marm</span></samp> or <samp><span class="option">-mthumb</span></samp>. 606This option is only supported on ARM targets. 607 608 <br><dt><code>--with-stack-offset=</code><var>num</var><dd>This option sets the default for the -mstack-offset=<var>num</var> option, 609and will thus generally also control the setting of this option for 610libraries. This option is only supported on Epiphany targets. 611 612 <br><dt><code>--with-fpmath=</code><var>isa</var><dd>This options sets <samp><span class="option">-mfpmath=sse</span></samp> by default and specifies the default 613ISA for floating-point arithmetics. You can select either ‘<samp><span class="samp">sse</span></samp>’ which 614enables <samp><span class="option">-msse2</span></samp> or ‘<samp><span class="samp">avx</span></samp>’ which enables <samp><span class="option">-mavx</span></samp> by default. 615This option is only supported on i386 and x86-64 targets. 616 617 <br><dt><code>--with-fp-32=</code><var>mode</var><dd>On MIPS targets, set the default value for the <samp><span class="option">-mfp</span></samp> option when using 618the o32 ABI. The possibilities for <var>mode</var> are: 619 <dl> 620<dt><code>32</code><dd>Use the o32 FP32 ABI extension, as with the <samp><span class="option">-mfp32</span></samp> command-line 621option. 622<br><dt><code>xx</code><dd>Use the o32 FPXX ABI extension, as with the <samp><span class="option">-mfpxx</span></samp> command-line 623option. 624<br><dt><code>64</code><dd>Use the o32 FP64 ABI extension, as with the <samp><span class="option">-mfp64</span></samp> command-line 625option. 626</dl> 627 In the absence of this configuration option the default is to use the o32 628FP32 ABI extension. 629 630 <br><dt><code>--with-odd-spreg-32</code><dd>On MIPS targets, set the <samp><span class="option">-modd-spreg</span></samp> option by default when using 631the o32 ABI. 632 633 <br><dt><code>--without-odd-spreg-32</code><dd>On MIPS targets, set the <samp><span class="option">-mno-odd-spreg</span></samp> option by default when using 634the o32 ABI. This is normally used in conjunction with 635<samp><span class="option">--with-fp-32=64</span></samp> in order to target the o32 FP64A ABI extension. 636 637 <br><dt><code>--with-nan=</code><var>encoding</var><dd>On MIPS targets, set the default encoding convention to use for the 638special not-a-number (NaN) IEEE 754 floating-point data. The 639possibilities for <var>encoding</var> are: 640 <dl> 641<dt><code>legacy</code><dd>Use the legacy encoding, as with the <samp><span class="option">-mnan=legacy</span></samp> command-line 642option. 643<br><dt><code>2008</code><dd>Use the 754-2008 encoding, as with the <samp><span class="option">-mnan=2008</span></samp> command-line 644option. 645</dl> 646 To use this configuration option you must have an assembler version 647installed that supports the <samp><span class="option">-mnan=</span></samp> command-line option too. 648In the absence of this configuration option the default convention is 649the legacy encoding, as when neither of the <samp><span class="option">-mnan=2008</span></samp> and 650<samp><span class="option">-mnan=legacy</span></samp> command-line options has been used. 651 652 <br><dt><code>--with-divide=</code><var>type</var><dd>Specify how the compiler should generate code for checking for 653division by zero. This option is only supported on the MIPS target. 654The possibilities for <var>type</var> are: 655 <dl> 656<dt><code>traps</code><dd>Division by zero checks use conditional traps (this is the default on 657systems that support conditional traps). 658<br><dt><code>breaks</code><dd>Division by zero checks use the break instruction. 659</dl> 660 661 <!-- If you make -with-llsc the default for additional targets, --> 662 <!-- update the -with-llsc description in the MIPS section below. --> 663 <br><dt><code>--with-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mllsc</span></samp> the default when no 664<samp><span class="option">-mno-llsc</span></samp> option is passed. This is the default for 665Linux-based targets, as the kernel will emulate them if the ISA does 666not provide them. 667 668 <br><dt><code>--without-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mno-llsc</span></samp> the default when no 669<samp><span class="option">-mllsc</span></samp> option is passed. 670 671 <br><dt><code>--with-synci</code><dd>On MIPS targets, make <samp><span class="option">-msynci</span></samp> the default when no 672<samp><span class="option">-mno-synci</span></samp> option is passed. 673 674 <br><dt><code>--without-synci</code><dd>On MIPS targets, make <samp><span class="option">-mno-synci</span></samp> the default when no 675<samp><span class="option">-msynci</span></samp> option is passed. This is the default. 676 677 <br><dt><code>--with-mips-plt</code><dd>On MIPS targets, make use of copy relocations and PLTs. 678These features are extensions to the traditional 679SVR4-based MIPS ABIs and require support from GNU binutils 680and the runtime C library. 681 682 <br><dt><code>--enable-__cxa_atexit</code><dd>Define if you want to use __cxa_atexit, rather than atexit, to 683register C++ destructors for local statics and global objects. 684This is essential for fully standards-compliant handling of 685destructors, but requires __cxa_atexit in libc. This option is currently 686only available on systems with GNU libc. When enabled, this will cause 687<samp><span class="option">-fuse-cxa-atexit</span></samp> to be passed by default. 688 689 <br><dt><code>--enable-gnu-indirect-function</code><dd>Define if you want to enable the <code>ifunc</code> attribute. This option is 690currently only available on systems with GNU libc on certain targets. 691 692 <br><dt><code>--enable-target-optspace</code><dd>Specify that target 693libraries should be optimized for code space instead of code speed. 694This is the default for the m32r platform. 695 696 <br><dt><code>--with-cpp-install-dir=</code><var>dirname</var><dd>Specify that the user visible <samp><span class="command">cpp</span></samp> program should be installed 697in <samp><var>prefix</var><span class="file">/</span><var>dirname</var><span class="file">/cpp</span></samp>, in addition to <var>bindir</var>. 698 699 <br><dt><code>--enable-comdat</code><dd>Enable COMDAT group support. This is primarily used to override the 700automatically detected value. 701 702 <br><dt><code>--enable-initfini-array</code><dd>Force the use of sections <code>.init_array</code> and <code>.fini_array</code> 703(instead of <code>.init</code> and <code>.fini</code>) for constructors and 704destructors. Option <samp><span class="option">--disable-initfini-array</span></samp> has the 705opposite effect. If neither option is specified, the configure script 706will try to guess whether the <code>.init_array</code> and 707<code>.fini_array</code> sections are supported and, if they are, use them. 708 709 <br><dt><code>--enable-link-mutex</code><dd>When building GCC, use a mutex to avoid linking the compilers for 710multiple languages at the same time, to avoid thrashing on build 711systems with limited free memory. The default is not to use such a mutex. 712 713 <br><dt><code>--enable-maintainer-mode</code><dd>The build rules that regenerate the Autoconf and Automake output files as 714well as the GCC master message catalog <samp><span class="file">gcc.pot</span></samp> are normally 715disabled. This is because it can only be rebuilt if the complete source 716tree is present. If you have changed the sources and want to rebuild the 717catalog, configuring with <samp><span class="option">--enable-maintainer-mode</span></samp> will enable 718this. Note that you need a recent version of the <code>gettext</code> tools 719to do so. 720 721 <br><dt><code>--disable-bootstrap</code><dd>For a native build, the default configuration is to perform 722a 3-stage bootstrap of the compiler when ‘<samp><span class="samp">make</span></samp>’ is invoked, 723testing that GCC can compile itself correctly. If you want to disable 724this process, you can configure with <samp><span class="option">--disable-bootstrap</span></samp>. 725 726 <br><dt><code>--enable-bootstrap</code><dd>In special cases, you may want to perform a 3-stage build 727even if the target and host triplets are different. 728This is possible when the host can run code compiled for 729the target (e.g. host is i686-linux, target is i486-linux). 730Starting from GCC 4.2, to do this you have to configure explicitly 731with <samp><span class="option">--enable-bootstrap</span></samp>. 732 733 <br><dt><code>--enable-generated-files-in-srcdir</code><dd>Neither the .c and .h files that are generated from Bison and flex nor the 734info manuals and man pages that are built from the .texi files are present 735in the SVN development tree. When building GCC from that development tree, 736or from one of our snapshots, those generated files are placed in your 737build directory, which allows for the source to be in a readonly 738directory. 739 740 <p>If you configure with <samp><span class="option">--enable-generated-files-in-srcdir</span></samp> then those 741generated files will go into the source directory. This is mainly intended 742for generating release or prerelease tarballs of the GCC sources, since it 743is not a requirement that the users of source releases to have flex, Bison, 744or makeinfo. 745 746 <br><dt><code>--enable-version-specific-runtime-libs</code><dd>Specify 747that runtime libraries should be installed in the compiler specific 748subdirectory (<samp><var>libdir</var><span class="file">/gcc</span></samp>) rather than the usual places. In 749addition, ‘<samp><span class="samp">libstdc++</span></samp>’'s include files will be installed into 750<samp><var>libdir</var></samp> unless you overruled it by using 751<samp><span class="option">--with-gxx-include-dir=</span><var>dirname</var></samp>. Using this option is 752particularly useful if you intend to use several versions of GCC in 753parallel. This is currently supported by ‘<samp><span class="samp">libgfortran</span></samp>’, 754‘<samp><span class="samp">libjava</span></samp>’, ‘<samp><span class="samp">libstdc++</span></samp>’, and ‘<samp><span class="samp">libobjc</span></samp>’. 755 756 <br><dt><code><a name="WithAixSoname"></a>--with-aix-soname=‘</code><samp><span class="samp">aix</span></samp><code>’, ‘</code><samp><span class="samp">svr4</span></samp><code>’ or ‘</code><samp><span class="samp">both</span></samp><code>’</code><dd>Traditional AIX shared library versioning (versioned <code>Shared Object</code> 757files as members of unversioned <code>Archive Library</code> files named 758‘<samp><span class="samp">lib.a</span></samp>’) causes numerous headaches for package managers. However, 759<code>Import Files</code> as members of <code>Archive Library</code> files allow for 760<strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4, 761where this is called the "SONAME". But as they prevent static linking, 762<code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the 763linker does search for ‘<samp><span class="samp">libNAME.so</span></samp>’ before ‘<samp><span class="samp">libNAME.a</span></samp>’ library 764filenames with the ‘<samp><span class="samp">-lNAME</span></samp>’ linker flag. 765 766 <p><a name="AixLdCommand"></a>For detailed information please refer to the AIX 767<a href="http://www-01.ibm.com/support/knowledgecenter/search/%22the%20ld%20command%2C%20also%20called%20the%20linkage%20editor%20or%20binder%22">ld Command</a> reference. 768 769 <p>As long as shared library creation is enabled, upon: 770 <dl> 771<dt><code>--with-aix-soname=aix</code><br><dt><code>--with-aix-soname=both</code><dd> A (traditional AIX) <code>Shared Archive Library</code> file is created: 772 <ul> 773 <li>using the ‘<samp><span class="samp">libNAME.a</span></samp>’ filename scheme 774 <li>with the <code>Shared Object</code> file as archive member named 775 ‘<samp><span class="samp">libNAME.so.V</span></samp>’ (except for ‘<samp><span class="samp">libgcc_s</span></samp>’, where the <code>Shared 776 Object</code> file is named ‘<samp><span class="samp">shr.o</span></samp>’ for backwards compatibility), which 777 <ul> 778 <li>is used for runtime loading from inside the ‘<samp><span class="samp">libNAME.a</span></samp>’ file 779 <li>is used for dynamic loading via 780 <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code> 781 <li>is used for shared linking 782 <li>is used for static linking, so no separate <code>Static Archive 783 Library</code> file is needed 784 </ul> 785 </ul> 786 <br><dt><code>--with-aix-soname=both</code><br><dt><code>--with-aix-soname=svr4</code><dd> A (second) <code>Shared Archive Library</code> file is created: 787 <ul> 788 <li>using the ‘<samp><span class="samp">libNAME.so.V</span></samp>’ filename scheme 789 <li>with the <code>Shared Object</code> file as archive member named 790 ‘<samp><span class="samp">shr.o</span></samp>’, which 791 <ul> 792 <li>is created with the <code>-G linker flag</code> 793 <li>has the <code>F_LOADONLY</code> flag set 794 <li>is used for runtime loading from inside the ‘<samp><span class="samp">libNAME.so.V</span></samp>’ file 795 <li>is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)", 796 RTLD_MEMBER)</code> 797 </ul> 798 <li>with the <code>Import File</code> as archive member named ‘<samp><span class="samp">shr.imp</span></samp>’, 799 which 800 <ul> 801 <li>refers to ‘<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>’ as the "SONAME", to be recorded 802 in the <code>Loader Section</code> of subsequent binaries 803 <li>indicates whether ‘<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>’ is 32 or 64 bit 804 <li>lists all the public symbols exported by ‘<samp><span class="samp">lib.so.V(shr.o)</span></samp>’, 805 eventually decorated with the <code>‘</code><samp><span class="samp">weak</span></samp><code>’ Keyword</code> 806 <li>is necessary for shared linking against ‘<samp><span class="samp">lib.so.V(shr.o)</span></samp>’ 807 </ul> 808 </ul> 809 A symbolic link using the ‘<samp><span class="samp">libNAME.so</span></samp>’ filename scheme is created: 810 <ul> 811 <li>pointing to the ‘<samp><span class="samp">libNAME.so.V</span></samp>’ <code>Shared Archive Library</code> file 812 <li>to permit the <code>ld Command</code> to find ‘<samp><span class="samp">lib.so.V(shr.imp)</span></samp>’ via 813 the ‘<samp><span class="samp">-lNAME</span></samp>’ argument (requires <code>Runtime Linking</code> to be enabled) 814 <li>to permit dynamic loading of ‘<samp><span class="samp">lib.so.V(shr.o)</span></samp>’ without the need 815 to specify the version number via <code>dlopen("libNAME.so(shr.o)", 816 RTLD_MEMBER)</code> 817 </ul> 818 </dl> 819 820 <p>As long as static library creation is enabled, upon: 821 <dl> 822<dt><code>--with-aix-soname=svr4</code><dd> A <code>Static Archive Library</code> is created: 823 <ul> 824 <li>using the ‘<samp><span class="samp">libNAME.a</span></samp>’ filename scheme 825 <li>with all the <code>Static Object</code> files as archive members, which 826 <ul> 827 <li>are used for static linking 828 </ul> 829 </ul> 830 </dl> 831 832 <p>While the aix-soname=‘<samp><span class="samp">svr4</span></samp>’ option does not create <code>Shared Object</code> 833files as members of unversioned <code>Archive Library</code> files any more, package 834managers still are responsible to 835<a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files 836found as member of a previously installed unversioned <code>Archive Library</code> 837file into the newly installed <code>Archive Library</code> file with the same 838filename. 839 840 <p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code> 841enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors, 842requiring the use of either the <samp><span class="option">-Wl,-bbigtoc</span></samp> linker flag (seen to 843break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags, 844see “RS/6000 and PowerPC Options” in the main manual. 845 846 <p><samp><span class="option">--with-aix-soname</span></samp> is currently supported by ‘<samp><span class="samp">libgcc_s</span></samp>’ only, so 847this option is still experimental and not for normal use yet. 848 849 <p>Default is the traditional behavior <samp><span class="option">--with-aix-soname=‘</span><samp><span class="samp">aix</span></samp><span class="option">’</span></samp>. 850 851 <br><dt><code>--enable-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that only a particular subset of compilers and 852their runtime libraries should be built. For a list of valid values for 853<var>langN</var> you can issue the following command in the 854<samp><span class="file">gcc</span></samp> directory of your GCC source tree:<br> 855 <pre class="smallexample"> grep ^language= */config-lang.in 856</pre> 857 <p>Currently, you can use any of the following: 858<code>all</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>fortran</code>, 859<code>go</code>, <code>java</code>, <code>jit</code>, <code>lto</code>, <code>objc</code>, <code>obj-c++</code>. 860Building the Ada compiler has special requirements, see below. 861If you do not pass this flag, or specify the option <code>all</code>, then all 862default languages available in the <samp><span class="file">gcc</span></samp> sub-tree will be configured. 863Ada, Go, Jit, and Objective-C++ are not default languages. LTO is not a 864default language, but is built by default because <samp><span class="option">--enable-lto</span></samp> is 865enabled by default. The other languages are default languages. 866 867 <br><dt><code>--enable-stage1-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that a particular subset of compilers and their runtime 868libraries should be built with the system C compiler during stage 1 of 869the bootstrap process, rather than only in later stages with the 870bootstrapped C compiler. The list of valid values is the same as for 871<samp><span class="option">--enable-languages</span></samp>, and the option <code>all</code> will select all 872of the languages enabled by <samp><span class="option">--enable-languages</span></samp>. This option is 873primarily useful for GCC development; for instance, when a development 874version of the compiler cannot bootstrap due to compiler bugs, or when 875one is debugging front ends other than the C front end. When this 876option is used, one can then build the target libraries for the 877specified languages with the stage-1 compiler by using <samp><span class="command">make 878stage1-bubble all-target</span></samp>, or run the testsuite on the stage-1 compiler 879for the specified languages using <samp><span class="command">make stage1-start check-gcc</span></samp>. 880 881 <br><dt><code>--disable-libada</code><dd>Specify that the run-time libraries and tools used by GNAT should not 882be built. This can be useful for debugging, or for compatibility with 883previous Ada build procedures, when it was required to explicitly 884do a ‘<samp><span class="samp">make -C gcc gnatlib_and_tools</span></samp>’. 885 886 <br><dt><code>--disable-libsanitizer</code><dd>Specify that the run-time libraries for the various sanitizers should 887not be built. 888 889 <br><dt><code>--disable-libssp</code><dd>Specify that the run-time libraries for stack smashing protection 890should not be built. 891 892 <br><dt><code>--disable-libquadmath</code><dd>Specify that the GCC quad-precision math library should not be built. 893On some systems, the library is required to be linkable when building 894the Fortran front end, unless <samp><span class="option">--disable-libquadmath-support</span></samp> 895is used. 896 897 <br><dt><code>--disable-libquadmath-support</code><dd>Specify that the Fortran front end and <code>libgfortran</code> do not add 898support for <code>libquadmath</code> on systems supporting it. 899 900 <br><dt><code>--disable-libgomp</code><dd>Specify that the GNU Offloading and Multi Processing Runtime Library 901should not be built. 902 903 <br><dt><code>--disable-libvtv</code><dd>Specify that the run-time libraries used by vtable verification 904should not be built. 905 906 <br><dt><code>--with-dwarf2</code><dd>Specify that the compiler should 907use DWARF 2 debugging information as the default. 908 909 <br><dt><code>--with-advance-toolchain=</code><var>at</var><dd>On 64-bit PowerPC Linux systems, configure the compiler to use the 910header files, library files, and the dynamic linker from the Advance 911Toolchain release <var>at</var> instead of the default versions that are 912provided by the Linux distribution. In general, this option is 913intended for the developers of GCC, and it is not intended for general 914use. 915 916 <br><dt><code>--enable-targets=all</code><dt><code>--enable-targets=</code><var>target_list</var><dd>Some GCC targets, e.g. powerpc64-linux, build bi-arch compilers. 917These are compilers that are able to generate either 64-bit or 32-bit 918code. Typically, the corresponding 32-bit target, e.g. 919powerpc-linux for powerpc64-linux, only generates 32-bit code. This 920option enables the 32-bit target to be a bi-arch compiler, which is 921useful when you want a bi-arch compiler that defaults to 32-bit, and 922you are building a bi-arch or multi-arch binutils in a combined tree. 923On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64), 924defaulted to o32. 925Currently, this option only affects sparc-linux, powerpc-linux, x86-linux, 926mips-linux and s390-linux. 927 928 <br><dt><code>--enable-default-pie</code><dd>Turn on <samp><span class="option">-fPIE</span></samp> and <samp><span class="option">-pie</span></samp> by default. 929 930 <br><dt><code>--enable-secureplt</code><dd>This option enables <samp><span class="option">-msecure-plt</span></samp> by default for powerpc-linux. 931See “RS/6000 and PowerPC Options” in the main manual 932 933 <br><dt><code>--enable-default-ssp</code><dd>Turn on <samp><span class="option">-fstack-protector-strong</span></samp> by default. 934 935 <br><dt><code>--enable-cld</code><dd>This option enables <samp><span class="option">-mcld</span></samp> by default for 32-bit x86 targets. 936See “i386 and x86-64 Options” in the main manual 937 938 <br><dt><code>--enable-win32-registry</code><dt><code>--enable-win32-registry=</code><var>key</var><dt><code>--disable-win32-registry</code><dd>The <samp><span class="option">--enable-win32-registry</span></samp> option enables Microsoft Windows-hosted GCC 939to look up installations paths in the registry using the following key: 940 941 <pre class="smallexample"> <code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\</code><var>key</var> 942</pre> 943 <p><var>key</var> defaults to GCC version number, and can be overridden by the 944<samp><span class="option">--enable-win32-registry=</span><var>key</var></samp> option. Vendors and distributors 945who use custom installers are encouraged to provide a different key, 946perhaps one comprised of vendor name and GCC version number, to 947avoid conflict with existing installations. This feature is enabled 948by default, and can be disabled by <samp><span class="option">--disable-win32-registry</span></samp> 949option. This option has no effect on the other hosts. 950 951 <br><dt><code>--nfp</code><dd>Specify that the machine does not have a floating point unit. This 952option only applies to ‘<samp><span class="samp">m68k-sun-sunos</span><var>n</var></samp>’. On any other 953system, <samp><span class="option">--nfp</span></samp> has no effect. 954 955 <br><dt><code>--enable-werror</code><dt><code>--disable-werror</code><dt><code>--enable-werror=yes</code><dt><code>--enable-werror=no</code><dd>When you specify this option, it controls whether certain files in the 956compiler are built with <samp><span class="option">-Werror</span></samp> in bootstrap stage2 and later. 957If you don't specify it, <samp><span class="option">-Werror</span></samp> is turned on for the main 958development trunk. However it defaults to off for release branches and 959final releases. The specific files which get <samp><span class="option">-Werror</span></samp> are 960controlled by the Makefiles. 961 962 <br><dt><code>--enable-checking</code><dt><code>--enable-checking=</code><var>list</var><dd>When you specify this option, the compiler is built to perform internal 963consistency checks of the requested complexity. This does not change the 964generated code, but adds error checking within the compiler. This will 965slow down the compiler and may only work properly if you are building 966the compiler with GCC. This is ‘<samp><span class="samp">yes</span></samp>’ by default when building 967from SVN or snapshots, but ‘<samp><span class="samp">release</span></samp>’ for releases. The default 968for building the stage1 compiler is ‘<samp><span class="samp">yes</span></samp>’. More control 969over the checks may be had by specifying <var>list</var>. The categories of 970checks available are ‘<samp><span class="samp">yes</span></samp>’ (most common checks 971‘<samp><span class="samp">assert,misc,tree,gc,rtlflag,runtime</span></samp>’), ‘<samp><span class="samp">no</span></samp>’ (no checks at 972all), ‘<samp><span class="samp">all</span></samp>’ (all but ‘<samp><span class="samp">valgrind</span></samp>’), ‘<samp><span class="samp">release</span></samp>’ (cheapest 973checks ‘<samp><span class="samp">assert,runtime</span></samp>’) or ‘<samp><span class="samp">none</span></samp>’ (same as ‘<samp><span class="samp">no</span></samp>’). 974Individual checks can be enabled with these flags ‘<samp><span class="samp">assert</span></samp>’, 975‘<samp><span class="samp">df</span></samp>’, ‘<samp><span class="samp">fold</span></samp>’, ‘<samp><span class="samp">gc</span></samp>’, ‘<samp><span class="samp">gcac</span></samp>’ ‘<samp><span class="samp">misc</span></samp>’, ‘<samp><span class="samp">rtl</span></samp>’, 976‘<samp><span class="samp">rtlflag</span></samp>’, ‘<samp><span class="samp">runtime</span></samp>’, ‘<samp><span class="samp">tree</span></samp>’, and ‘<samp><span class="samp">valgrind</span></samp>’. 977 978 <p>The ‘<samp><span class="samp">valgrind</span></samp>’ check requires the external <samp><span class="command">valgrind</span></samp> 979simulator, available from <a href="http://valgrind.org/">http://valgrind.org/</a>. The 980‘<samp><span class="samp">df</span></samp>’, ‘<samp><span class="samp">rtl</span></samp>’, ‘<samp><span class="samp">gcac</span></samp>’ and ‘<samp><span class="samp">valgrind</span></samp>’ checks are very expensive. 981To disable all checking, ‘<samp><span class="samp">--disable-checking</span></samp>’ or 982‘<samp><span class="samp">--enable-checking=none</span></samp>’ must be explicitly requested. Disabling 983assertions will make the compiler and runtime slightly faster but 984increase the risk of undetected internal errors causing wrong code to be 985generated. 986 987 <br><dt><code>--disable-stage1-checking</code><dt><code>--enable-stage1-checking</code><dt><code>--enable-stage1-checking=</code><var>list</var><dd>If no <samp><span class="option">--enable-checking</span></samp> option is specified the stage1 988compiler will be built with ‘<samp><span class="samp">yes</span></samp>’ checking enabled, otherwise 989the stage1 checking flags are the same as specified by 990<samp><span class="option">--enable-checking</span></samp>. To build the stage1 compiler with 991different checking options use <samp><span class="option">--enable-stage1-checking</span></samp>. 992The list of checking options is the same as for <samp><span class="option">--enable-checking</span></samp>. 993If your system is too slow or too small to bootstrap a released compiler 994with checking for stage1 enabled, you can use ‘<samp><span class="samp">--disable-stage1-checking</span></samp>’ 995to disable checking for the stage1 compiler. 996 997 <br><dt><code>--enable-coverage</code><dt><code>--enable-coverage=</code><var>level</var><dd>With this option, the compiler is built to collect self coverage 998information, every time it is run. This is for internal development 999purposes, and only works when the compiler is being built with gcc. The 1000<var>level</var> argument controls whether the compiler is built optimized or 1001not, values are ‘<samp><span class="samp">opt</span></samp>’ and ‘<samp><span class="samp">noopt</span></samp>’. For coverage analysis you 1002want to disable optimization, for performance analysis you want to 1003enable optimization. When coverage is enabled, the default level is 1004without optimization. 1005 1006 <br><dt><code>--enable-gather-detailed-mem-stats</code><dd>When this option is specified more detailed information on memory 1007allocation is gathered. This information is printed when using 1008<samp><span class="option">-fmem-report</span></samp>. 1009 1010 <br><dt><code>--enable-valgrind-annotations</code><dd>Mark selected memory related operations in the compiler when run under 1011valgrind to suppress false positives. 1012 1013 <br><dt><code>--enable-nls</code><dt><code>--disable-nls</code><dd>The <samp><span class="option">--enable-nls</span></samp> option enables Native Language Support (NLS), 1014which lets GCC output diagnostics in languages other than American 1015English. Native Language Support is enabled by default if not doing a 1016canadian cross build. The <samp><span class="option">--disable-nls</span></samp> option disables NLS. 1017 1018 <br><dt><code>--with-included-gettext</code><dd>If NLS is enabled, the <samp><span class="option">--with-included-gettext</span></samp> option causes the build 1019procedure to prefer its copy of GNU <samp><span class="command">gettext</span></samp>. 1020 1021 <br><dt><code>--with-catgets</code><dd>If NLS is enabled, and if the host lacks <code>gettext</code> but has the 1022inferior <code>catgets</code> interface, the GCC build procedure normally 1023ignores <code>catgets</code> and instead uses GCC's copy of the GNU 1024<code>gettext</code> library. The <samp><span class="option">--with-catgets</span></samp> option causes the 1025build procedure to use the host's <code>catgets</code> in this situation. 1026 1027 <br><dt><code>--with-libiconv-prefix=</code><var>dir</var><dd>Search for libiconv header files in <samp><var>dir</var><span class="file">/include</span></samp> and 1028libiconv library files in <samp><var>dir</var><span class="file">/lib</span></samp>. 1029 1030 <br><dt><code>--enable-obsolete</code><dd>Enable configuration for an obsoleted system. If you attempt to 1031configure GCC for a system (build, host, or target) which has been 1032obsoleted, and you do not specify this flag, configure will halt with an 1033error message. 1034 1035 <p>All support for systems which have been obsoleted in one release of GCC 1036is removed entirely in the next major release, unless someone steps 1037forward to maintain the port. 1038 1039 <br><dt><code>--enable-decimal-float</code><dt><code>--enable-decimal-float=yes</code><dt><code>--enable-decimal-float=no</code><dt><code>--enable-decimal-float=bid</code><dt><code>--enable-decimal-float=dpd</code><dt><code>--disable-decimal-float</code><dd>Enable (or disable) support for the C decimal floating point extension 1040that is in the IEEE 754-2008 standard. This is enabled by default only 1041on PowerPC, i386, and x86_64 GNU/Linux systems. Other systems may also 1042support it, but require the user to specifically enable it. You can 1043optionally control which decimal floating point format is used (either 1044‘<samp><span class="samp">bid</span></samp>’ or ‘<samp><span class="samp">dpd</span></samp>’). The ‘<samp><span class="samp">bid</span></samp>’ (binary integer decimal) 1045format is default on i386 and x86_64 systems, and the ‘<samp><span class="samp">dpd</span></samp>’ 1046(densely packed decimal) format is default on PowerPC systems. 1047 1048 <br><dt><code>--enable-fixed-point</code><dt><code>--disable-fixed-point</code><dd>Enable (or disable) support for C fixed-point arithmetic. 1049This option is enabled by default for some targets (such as MIPS) which 1050have hardware-support for fixed-point operations. On other targets, you 1051may enable this option manually. 1052 1053 <br><dt><code>--with-long-double-128</code><dd>Specify if <code>long double</code> type should be 128-bit by default on selected 1054GNU/Linux architectures. If using <code>--without-long-double-128</code>, 1055<code>long double</code> will be by default 64-bit, the same as <code>double</code> type. 1056When neither of these configure options are used, the default will be 1057128-bit <code>long double</code> when built against GNU C Library 2.4 and later, 105864-bit <code>long double</code> otherwise. 1059 1060 <br><dt><code>--enable-fdpic</code><dd>On SH Linux systems, generate ELF FDPIC code. 1061 1062 <br><dt><code>--with-gmp=</code><var>pathname</var><dt><code>--with-gmp-include=</code><var>pathname</var><dt><code>--with-gmp-lib=</code><var>pathname</var><dt><code>--with-mpfr=</code><var>pathname</var><dt><code>--with-mpfr-include=</code><var>pathname</var><dt><code>--with-mpfr-lib=</code><var>pathname</var><dt><code>--with-mpc=</code><var>pathname</var><dt><code>--with-mpc-include=</code><var>pathname</var><dt><code>--with-mpc-lib=</code><var>pathname</var><dd>If you want to build GCC but do not have the GMP library, the MPFR 1063library and/or the MPC library installed in a standard location and 1064do not have their sources present in the GCC source tree then you 1065can explicitly specify the directory where they are installed 1066(‘<samp><span class="samp">--with-gmp=</span><var>gmpinstalldir</var></samp>’, 1067‘<samp><span class="samp">--with-mpfr=</span><var>mpfrinstalldir</var></samp>’, 1068‘<samp><span class="samp">--with-mpc=</span><var>mpcinstalldir</var></samp>’). The 1069<samp><span class="option">--with-gmp=</span><var>gmpinstalldir</var></samp> option is shorthand for 1070<samp><span class="option">--with-gmp-lib=</span><var>gmpinstalldir</var><span class="option">/lib</span></samp> and 1071<samp><span class="option">--with-gmp-include=</span><var>gmpinstalldir</var><span class="option">/include</span></samp>. Likewise the 1072<samp><span class="option">--with-mpfr=</span><var>mpfrinstalldir</var></samp> option is shorthand for 1073<samp><span class="option">--with-mpfr-lib=</span><var>mpfrinstalldir</var><span class="option">/lib</span></samp> and 1074<samp><span class="option">--with-mpfr-include=</span><var>mpfrinstalldir</var><span class="option">/include</span></samp>, also the 1075<samp><span class="option">--with-mpc=</span><var>mpcinstalldir</var></samp> option is shorthand for 1076<samp><span class="option">--with-mpc-lib=</span><var>mpcinstalldir</var><span class="option">/lib</span></samp> and 1077<samp><span class="option">--with-mpc-include=</span><var>mpcinstalldir</var><span class="option">/include</span></samp>. If these 1078shorthand assumptions are not correct, you can use the explicit 1079include and lib options directly. You might also need to ensure the 1080shared libraries can be found by the dynamic linker when building and 1081using GCC, for example by setting the runtime shared library path 1082variable (<samp><span class="env">LD_LIBRARY_PATH</span></samp> on GNU/Linux and Solaris systems). 1083 1084 <p>These flags are applicable to the host platform only. When building 1085a cross compiler, they will not be used to configure target libraries. 1086 1087 <br><dt><code>--with-isl=</code><var>pathname</var><dt><code>--with-isl-include=</code><var>pathname</var><dt><code>--with-isl-lib=</code><var>pathname</var><dd>If you do not have the isl library installed in a standard location and you 1088want to build GCC, you can explicitly specify the directory where it is 1089installed (‘<samp><span class="samp">--with-isl=</span><var>islinstalldir</var></samp>’). The 1090<samp><span class="option">--with-isl=</span><var>islinstalldir</var></samp> option is shorthand for 1091<samp><span class="option">--with-isl-lib=</span><var>islinstalldir</var><span class="option">/lib</span></samp> and 1092<samp><span class="option">--with-isl-include=</span><var>islinstalldir</var><span class="option">/include</span></samp>. If this 1093shorthand assumption is not correct, you can use the explicit 1094include and lib options directly. 1095 1096 <p>These flags are applicable to the host platform only. When building 1097a cross compiler, they will not be used to configure target libraries. 1098 1099 <br><dt><code>--with-stage1-ldflags=</code><var>flags</var><dd>This option may be used to set linker flags to be used when linking 1100stage 1 of GCC. These are also used when linking GCC if configured with 1101<samp><span class="option">--disable-bootstrap</span></samp>. If <samp><span class="option">--with-stage1-libs</span></samp> is not set to a 1102value, then the default is ‘<samp><span class="samp">-static-libstdc++ -static-libgcc</span></samp>’, if 1103supported. 1104 1105 <br><dt><code>--with-stage1-libs=</code><var>libs</var><dd>This option may be used to set libraries to be used when linking stage 1 1106of GCC. These are also used when linking GCC if configured with 1107<samp><span class="option">--disable-bootstrap</span></samp>. 1108 1109 <br><dt><code>--with-boot-ldflags=</code><var>flags</var><dd>This option may be used to set linker flags to be used when linking 1110stage 2 and later when bootstrapping GCC. If –with-boot-libs 1111is not is set to a value, then the default is 1112‘<samp><span class="samp">-static-libstdc++ -static-libgcc</span></samp>’. 1113 1114 <br><dt><code>--with-boot-libs=</code><var>libs</var><dd>This option may be used to set libraries to be used when linking stage 2 1115and later when bootstrapping GCC. 1116 1117 <br><dt><code>--with-debug-prefix-map=</code><var>map</var><dd>Convert source directory names using <samp><span class="option">-fdebug-prefix-map</span></samp> when 1118building runtime libraries. ‘<samp><var>map</var></samp>’ is a space-separated 1119list of maps of the form ‘<samp><var>old</var><span class="samp">=</span><var>new</var></samp>’. 1120 1121 <br><dt><code>--enable-linker-build-id</code><dd>Tells GCC to pass <samp><span class="option">--build-id</span></samp> option to the linker for all final 1122links (links performed without the <samp><span class="option">-r</span></samp> or <samp><span class="option">--relocatable</span></samp> 1123option), if the linker supports it. If you specify 1124<samp><span class="option">--enable-linker-build-id</span></samp>, but your linker does not 1125support <samp><span class="option">--build-id</span></samp> option, a warning is issued and the 1126<samp><span class="option">--enable-linker-build-id</span></samp> option is ignored. The default is off. 1127 1128 <br><dt><code>--with-linker-hash-style=</code><var>choice</var><dd>Tells GCC to pass <samp><span class="option">--hash-style=</span><var>choice</var></samp> option to the 1129linker for all final links. <var>choice</var> can be one of 1130‘<samp><span class="samp">sysv</span></samp>’, ‘<samp><span class="samp">gnu</span></samp>’, and ‘<samp><span class="samp">both</span></samp>’ where ‘<samp><span class="samp">sysv</span></samp>’ is the default. 1131 1132 <br><dt><code>--enable-gnu-unique-object</code><dt><code>--disable-gnu-unique-object</code><dd>Tells GCC to use the gnu_unique_object relocation for C++ template 1133static data members and inline function local statics. Enabled by 1134default for a toolchain with an assembler that accepts it and 1135GLIBC 2.11 or above, otherwise disabled. 1136 1137 <br><dt><code>--with-diagnostics-color=</code><var>choice</var><dd>Tells GCC to use <var>choice</var> as the default for <samp><span class="option">-fdiagnostics-color=</span></samp> 1138option (if not used explicitly on the command line). <var>choice</var> 1139can be one of ‘<samp><span class="samp">never</span></samp>’, ‘<samp><span class="samp">auto</span></samp>’, ‘<samp><span class="samp">always</span></samp>’, and ‘<samp><span class="samp">auto-if-env</span></samp>’ 1140where ‘<samp><span class="samp">auto</span></samp>’ is the default. ‘<samp><span class="samp">auto-if-env</span></samp>’ means that 1141<samp><span class="option">-fdiagnostics-color=auto</span></samp> will be the default if <code>GCC_COLORS</code> 1142is present and non-empty in the environment, and 1143<samp><span class="option">-fdiagnostics-color=never</span></samp> otherwise. 1144 1145 <br><dt><code>--enable-lto</code><dt><code>--disable-lto</code><dd>Enable support for link-time optimization (LTO). This is enabled by 1146default, and may be disabled using <samp><span class="option">--disable-lto</span></samp>. 1147 1148 <br><dt><code>--enable-linker-plugin-configure-flags=FLAGS</code><dt><code>--enable-linker-plugin-flags=FLAGS</code><dd>By default, linker plugins (such as the LTO plugin) are built for the 1149host system architecture. For the case that the linker has a 1150different (but run-time compatible) architecture, these flags can be 1151specified to build plugins that are compatible to the linker. For 1152example, if you are building GCC for a 64-bit x86_64 1153(‘<samp><span class="samp">x86_64-unknown-linux-gnu</span></samp>’) host system, but have a 32-bit x86 1154GNU/Linux (‘<samp><span class="samp">i686-pc-linux-gnu</span></samp>’) linker executable (which is 1155executable on the former system), you can configure GCC as follows for 1156getting compatible linker plugins: 1157 1158 <pre class="smallexample"> % <var>srcdir</var>/configure \ 1159 --host=x86_64-unknown-linux-gnu \ 1160 --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \ 1161 --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib' 1162</pre> 1163 <br><dt><code>--with-plugin-ld=</code><var>pathname</var><dd>Enable an alternate linker to be used at link-time optimization (LTO) 1164link time when <samp><span class="option">-fuse-linker-plugin</span></samp> is enabled. 1165This linker should have plugin support such as gold starting with 1166version 2.20 or GNU ld starting with version 2.21. 1167See <samp><span class="option">-fuse-linker-plugin</span></samp> for details. 1168 1169 <br><dt><code>--enable-canonical-system-headers</code><dt><code>--disable-canonical-system-headers</code><dd>Enable system header path canonicalization for <samp><span class="file">libcpp</span></samp>. This can 1170produce shorter header file paths in diagnostics and dependency output 1171files, but these changed header paths may conflict with some compilation 1172environments. Enabled by default, and may be disabled using 1173<samp><span class="option">--disable-canonical-system-headers</span></samp>. 1174 1175 <br><dt><code>--with-glibc-version=</code><var>major</var><code>.</code><var>minor</var><dd>Tell GCC that when the GNU C Library (glibc) is used on the target it 1176will be version <var>major</var>.<var>minor</var> or later. Normally this can 1177be detected from the C library's header files, but this option may be 1178needed when bootstrapping a cross toolchain without the header files 1179available for building the initial bootstrap compiler. 1180 1181 <p>If GCC is configured with some multilibs that use glibc and some that 1182do not, this option applies only to the multilibs that use glibc. 1183However, such configurations may not work well as not all the relevant 1184configuration in GCC is on a per-multilib basis. 1185 1186 <br><dt><code>--enable-as-accelerator-for=</code><var>target</var><dd>Build as offload target compiler. Specify offload host triple by <var>target</var>. 1187 1188 <br><dt><code>--enable-offload-targets=</code><var>target1</var><code>[=</code><var>path1</var><code>],...,</code><var>targetN</var><code>[=</code><var>pathN</var><code>]</code><dd>Enable offloading to targets <var>target1</var>, <small class="dots">...</small>, <var>targetN</var>. 1189Offload compilers are expected to be already installed. Default search 1190path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by 1191specifying paths <var>path1</var>, <small class="dots">...</small>, <var>pathN</var>. 1192 1193 <pre class="smallexample"> % <var>srcdir</var>/configure \ 1194 --enable-offload-target=i686-unknown-linux-gnu=/path/to/i686/compiler,x86_64-pc-linux-gnu 1195</pre> 1196 <p>If ‘<samp><span class="samp">hsa</span></samp>’ is specified as one of the targets, the compiler will be 1197built with support for HSA GPU accelerators. Because the same 1198compiler will emit the accelerator code, no path should be specified. 1199 1200 <br><dt><code>--with-hsa-runtime=</code><var>pathname</var><dt><code>--with-hsa-runtime-include=</code><var>pathname</var><dt><code>--with-hsa-runtime-lib=</code><var>pathname</var><dd> 1201If you configure GCC with HSA offloading but do not have the HSA 1202run-time library installed in a standard location then you can 1203explicitly specify the directory where they are installed. The 1204<samp><span class="option">--with-hsa-runtime=</span><var>hsainstalldir</var></samp> option is a 1205shorthand for 1206<samp><span class="option">--with-hsa-runtime-lib=</span><var>hsainstalldir</var><span class="option">/lib</span></samp> and 1207<samp><span class="option">--with-hsa-runtime-include=</span><var>hsainstalldir</var><span class="option">/include</span></samp>. 1208 1209 <br><dt><code>--with-hsa-kmt-lib=</code><var>pathname</var><dd> 1210If you configure GCC with HSA offloading but do not have the HSA 1211KMT library installed in a standard location then you can 1212explicitly specify the directory where it resides. 1213</dl> 1214 1215<h4 class="subheading"><a name="TOC3"></a>Cross-Compiler-Specific Options</h4> 1216 1217<p>The following options only apply to building cross compilers. 1218 1219 <dl> 1220<dt><code>--with-sysroot</code><dt><code>--with-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the root of a tree that contains 1221(a subset of) the root filesystem of the target operating system. 1222Target system headers, libraries and run-time object files will be 1223searched for in there. More specifically, this acts as if 1224<samp><span class="option">--sysroot=</span><var>dir</var></samp> was added to the default options of the built 1225compiler. The specified directory is not copied into the 1226install tree, unlike the options <samp><span class="option">--with-headers</span></samp> and 1227<samp><span class="option">--with-libs</span></samp> that this option obsoletes. The default value, 1228in case <samp><span class="option">--with-sysroot</span></samp> is not given an argument, is 1229<samp><span class="option">${gcc_tooldir}/sys-root</span></samp>. If the specified directory is a 1230subdirectory of <samp><span class="option">${exec_prefix}</span></samp>, then it will be found relative to 1231the GCC binaries if the installation tree is moved. 1232 1233 <p>This option affects the system root for the compiler used to build 1234target libraries (which runs on the build system) and the compiler newly 1235installed with <code>make install</code>; it does not affect the compiler which is 1236used to build GCC itself. 1237 1238 <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp> 1239option then the compiler will search that directory within <var>dirname</var> for 1240native system headers rather than the default <samp><span class="file">/usr/include</span></samp>. 1241 1242 <br><dt><code>--with-build-sysroot</code><dt><code>--with-build-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the system root (see 1243<samp><span class="option">--with-sysroot</span></samp>) while building target libraries, instead of 1244the directory specified with <samp><span class="option">--with-sysroot</span></samp>. This option is 1245only useful when you are already using <samp><span class="option">--with-sysroot</span></samp>. You 1246can use <samp><span class="option">--with-build-sysroot</span></samp> when you are configuring with 1247<samp><span class="option">--prefix</span></samp> set to a directory that is different from the one in 1248which you are installing GCC and your target libraries. 1249 1250 <p>This option affects the system root for the compiler used to build 1251target libraries (which runs on the build system); it does not affect 1252the compiler which is used to build GCC itself. 1253 1254 <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp> 1255option then the compiler will search that directory within <var>dirname</var> for 1256native system headers rather than the default <samp><span class="file">/usr/include</span></samp>. 1257 1258 <br><dt><code>--with-headers</code><dt><code>--with-headers=</code><var>dir</var><dd>Deprecated in favor of <samp><span class="option">--with-sysroot</span></samp>. 1259Specifies that target headers are available when building a cross compiler. 1260The <var>dir</var> argument specifies a directory which has the target include 1261files. These include files will be copied into the <samp><span class="file">gcc</span></samp> install 1262directory. <em>This option with the </em><var>dir</var><em> argument is required</em> when 1263building a cross compiler, if <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp> 1264doesn't pre-exist. If <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp> does 1265pre-exist, the <var>dir</var> argument may be omitted. <samp><span class="command">fixincludes</span></samp> 1266will be run on these files to make them compatible with GCC. 1267 1268 <br><dt><code>--without-headers</code><dd>Tells GCC not use any target headers from a libc when building a cross 1269compiler. When crossing to GNU/Linux, you need the headers so GCC 1270can build the exception handling for libgcc. 1271 1272 <br><dt><code>--with-libs</code><dt><code>--with-libs="</code><var>dir1</var> <var>dir2</var><code> ... </code><var>dirN</var><code>"</code><dd>Deprecated in favor of <samp><span class="option">--with-sysroot</span></samp>. 1273Specifies a list of directories which contain the target runtime 1274libraries. These libraries will be copied into the <samp><span class="file">gcc</span></samp> install 1275directory. If the directory list is omitted, this option has no 1276effect. 1277 1278 <br><dt><code>--with-newlib</code><dd>Specifies that ‘<samp><span class="samp">newlib</span></samp>’ is 1279being used as the target C library. This causes <code>__eprintf</code> to be 1280omitted from <samp><span class="file">libgcc.a</span></samp> on the assumption that it will be provided by 1281‘<samp><span class="samp">newlib</span></samp>’. 1282 1283 <br><dt><code>--with-avrlibc</code><dd>Specifies that ‘<samp><span class="samp">AVR-Libc</span></samp>’ is 1284being used as the target C library. This causes float support 1285functions like <code>__addsf3</code> to be omitted from <samp><span class="file">libgcc.a</span></samp> on 1286the assumption that it will be provided by <samp><span class="file">libm.a</span></samp>. For more 1287technical details, cf. <a href="http://gcc.gnu.org/PR54461">PR54461</a>. 1288This option is only supported for the AVR target. It is not supported for 1289RTEMS configurations, which currently use newlib. The option is 1290supported since version 4.7.2 and is the default in 4.8.0 and newer. 1291 1292 <br><dt><code>--with-nds32-lib=</code><var>library</var><dd>Specifies that <var>library</var> setting is used for building <samp><span class="file">libgcc.a</span></samp>. 1293Currently, the valid <var>library</var> is ‘<samp><span class="samp">newlib</span></samp>’ or ‘<samp><span class="samp">mculib</span></samp>’. 1294This option is only supported for the NDS32 target. 1295 1296 <br><dt><code>--with-build-time-tools=</code><var>dir</var><dd>Specifies where to find the set of target tools (assembler, linker, etc.) 1297that will be used while building GCC itself. This option can be useful 1298if the directory layouts are different between the system you are building 1299GCC on, and the system where you will deploy it. 1300 1301 <p>For example, on an ‘<samp><span class="samp">ia64-hp-hpux</span></samp>’ system, you may have the GNU 1302assembler and linker in <samp><span class="file">/usr/bin</span></samp>, and the native tools in a 1303different path, and build a toolchain that expects to find the 1304native tools in <samp><span class="file">/usr/bin</span></samp>. 1305 1306 <p>When you use this option, you should ensure that <var>dir</var> includes 1307<samp><span class="command">ar</span></samp>, <samp><span class="command">as</span></samp>, <samp><span class="command">ld</span></samp>, <samp><span class="command">nm</span></samp>, 1308<samp><span class="command">ranlib</span></samp> and <samp><span class="command">strip</span></samp> if necessary, and possibly 1309<samp><span class="command">objdump</span></samp>. Otherwise, GCC may use an inconsistent set of 1310tools. 1311</dl> 1312 1313<h5 class="subsubheading"><a name="TOC4"></a>Overriding <samp><span class="command">configure</span></samp> test results</h5> 1314 1315<p>Sometimes, it might be necessary to override the result of some 1316<samp><span class="command">configure</span></samp> test, for example in order to ease porting to a new 1317system or work around a bug in a test. The toplevel <samp><span class="command">configure</span></samp> 1318script provides three variables for this: 1319 1320 <dl> 1321<dt><code>build_configargs</code><dd><a name="index-g_t_0040code_007bbuild_005fconfigargs_007d-3"></a>The contents of this variable is passed to all build <samp><span class="command">configure</span></samp> 1322scripts. 1323 1324 <br><dt><code>host_configargs</code><dd><a name="index-g_t_0040code_007bhost_005fconfigargs_007d-4"></a>The contents of this variable is passed to all host <samp><span class="command">configure</span></samp> 1325scripts. 1326 1327 <br><dt><code>target_configargs</code><dd><a name="index-g_t_0040code_007btarget_005fconfigargs_007d-5"></a>The contents of this variable is passed to all target <samp><span class="command">configure</span></samp> 1328scripts. 1329 1330 </dl> 1331 1332 <p>In order to avoid shell and <samp><span class="command">make</span></samp> quoting issues for complex 1333overrides, you can pass a setting for <samp><span class="env">CONFIG_SITE</span></samp> and set 1334variables in the site file. 1335 1336<h4 class="subheading"><a name="TOC5"></a>Java-Specific Options</h4> 1337 1338<p>The following option applies to the build of the Java front end. 1339 1340 <dl> 1341<dt><code>--disable-libgcj</code><dd>Specify that the run-time libraries 1342used by GCJ should not be built. This is useful in case you intend 1343to use GCJ with some other run-time, or you're going to install it 1344separately, or it just happens not to build on your particular 1345machine. In general, if the Java front end is enabled, the GCJ 1346libraries will be enabled too, unless they're known to not work on 1347the target platform. If GCJ is enabled but ‘<samp><span class="samp">libgcj</span></samp>’ isn't built, you 1348may need to port it; in this case, before modifying the top-level 1349<samp><span class="file">configure.ac</span></samp> so that ‘<samp><span class="samp">libgcj</span></samp>’ is enabled by default on this platform, 1350you may use <samp><span class="option">--enable-libgcj</span></samp> to override the default. 1351 1352 </dl> 1353 1354 <p>The following options apply to building ‘<samp><span class="samp">libgcj</span></samp>’. 1355 1356<h5 class="subsubheading"><a name="TOC6"></a>General Options</h5> 1357 1358 <dl> 1359<dt><code>--enable-java-maintainer-mode</code><dd>By default the ‘<samp><span class="samp">libjava</span></samp>’ build will not attempt to compile the 1360<samp><span class="file">.java</span></samp> source files to <samp><span class="file">.class</span></samp>. Instead, it will use the 1361<samp><span class="file">.class</span></samp> files from the source tree. If you use this option you 1362must have executables named <samp><span class="command">ecj1</span></samp> and <samp><span class="command">gjavah</span></samp> in your path 1363for use by the build. You must use this option if you intend to 1364modify any <samp><span class="file">.java</span></samp> files in <samp><span class="file">libjava</span></samp>. 1365 1366 <br><dt><code>--with-java-home=</code><var>dirname</var><dd>This ‘<samp><span class="samp">libjava</span></samp>’ option overrides the default value of the 1367‘<samp><span class="samp">java.home</span></samp>’ system property. It is also used to set 1368‘<samp><span class="samp">sun.boot.class.path</span></samp>’ to <samp><var>dirname</var><span class="file">/lib/rt.jar</span></samp>. By 1369default ‘<samp><span class="samp">java.home</span></samp>’ is set to <samp><var>prefix</var></samp> and 1370‘<samp><span class="samp">sun.boot.class.path</span></samp>’ to 1371<samp><var>datadir</var><span class="file">/java/libgcj-</span><var>version</var><span class="file">.jar</span></samp>. 1372 1373 <br><dt><code>--with-ecj-jar=</code><var>filename</var><dd>This option can be used to specify the location of an external jar 1374file containing the Eclipse Java compiler. A specially modified 1375version of this compiler is used by <samp><span class="command">gcj</span></samp> to parse 1376<samp><span class="file">.java</span></samp> source files. If this option is given, the 1377‘<samp><span class="samp">libjava</span></samp>’ build will create and install an <samp><span class="file">ecj1</span></samp> executable 1378which uses this jar file at runtime. 1379 1380 <p>If this option is not given, but an <samp><span class="file">ecj.jar</span></samp> file is found in 1381the topmost source tree at configure time, then the ‘<samp><span class="samp">libgcj</span></samp>’ 1382build will create and install <samp><span class="file">ecj1</span></samp>, and will also install the 1383discovered <samp><span class="file">ecj.jar</span></samp> into a suitable place in the install tree. 1384 1385 <p>If <samp><span class="file">ecj1</span></samp> is not installed, then the user will have to supply one 1386on his path in order for <samp><span class="command">gcj</span></samp> to properly parse <samp><span class="file">.java</span></samp> 1387source files. A suitable jar is available from 1388<a href="ftp://sourceware.org/pub/java/">ftp://sourceware.org/pub/java/</a>. 1389 1390 <br><dt><code>--disable-getenv-properties</code><dd>Don't set system properties from <samp><span class="env">GCJ_PROPERTIES</span></samp>. 1391 1392 <br><dt><code>--enable-hash-synchronization</code><dd>Use a global hash table for monitor locks. Ordinarily, 1393‘<samp><span class="samp">libgcj</span></samp>’'s ‘<samp><span class="samp">configure</span></samp>’ script automatically makes 1394the correct choice for this option for your platform. Only use 1395this if you know you need the library to be configured differently. 1396 1397 <br><dt><code>--enable-interpreter</code><dd>Enable the Java interpreter. The interpreter is automatically 1398enabled by default on all platforms that support it. This option 1399is really only useful if you want to disable the interpreter 1400(using <samp><span class="option">--disable-interpreter</span></samp>). 1401 1402 <br><dt><code>--disable-java-net</code><dd>Disable java.net. This disables the native part of java.net only, 1403using non-functional stubs for native method implementations. 1404 1405 <br><dt><code>--disable-jvmpi</code><dd>Disable JVMPI support. 1406 1407 <br><dt><code>--disable-libgcj-bc</code><dd>Disable BC ABI compilation of certain parts of libgcj. By default, 1408some portions of libgcj are compiled with <samp><span class="option">-findirect-dispatch</span></samp> 1409and <samp><span class="option">-fno-indirect-classes</span></samp>, allowing them to be overridden at 1410run-time. 1411 1412 <p>If <samp><span class="option">--disable-libgcj-bc</span></samp> is specified, libgcj is built without 1413these options. This allows the compile-time linker to resolve 1414dependencies when statically linking to libgcj. However it makes it 1415impossible to override the affected portions of libgcj at run-time. 1416 1417 <br><dt><code>--enable-reduced-reflection</code><dd>Build most of libgcj with <samp><span class="option">-freduced-reflection</span></samp>. This reduces 1418the size of libgcj at the expense of not being able to do accurate 1419reflection on the classes it contains. This option is safe if you 1420know that code using libgcj will never use reflection on the standard 1421runtime classes in libgcj (including using serialization, RMI or CORBA). 1422 1423 <br><dt><code>--with-ecos</code><dd>Enable runtime eCos target support. 1424 1425 <br><dt><code>--without-libffi</code><dd>Don't use ‘<samp><span class="samp">libffi</span></samp>’. This will disable the interpreter and JNI 1426support as well, as these require ‘<samp><span class="samp">libffi</span></samp>’ to work. 1427 1428 <br><dt><code>--enable-libgcj-debug</code><dd>Enable runtime debugging code. 1429 1430 <br><dt><code>--enable-libgcj-multifile</code><dd>If specified, causes all <samp><span class="file">.java</span></samp> source files to be 1431compiled into <samp><span class="file">.class</span></samp> files in one invocation of 1432‘<samp><span class="samp">gcj</span></samp>’. This can speed up build time, but is more 1433resource-intensive. If this option is unspecified or 1434disabled, ‘<samp><span class="samp">gcj</span></samp>’ is invoked once for each <samp><span class="file">.java</span></samp> 1435file to compile into a <samp><span class="file">.class</span></samp> file. 1436 1437 <br><dt><code>--with-libiconv-prefix=DIR</code><dd>Search for libiconv in <samp><span class="file">DIR/include</span></samp> and <samp><span class="file">DIR/lib</span></samp>. 1438 1439 <br><dt><code>--with-system-zlib</code><dd>Use installed ‘<samp><span class="samp">zlib</span></samp>’ rather than that included with GCC. 1440 1441 <br><dt><code>--with-win32-nlsapi=ansi, unicows or unicode</code><dd>Indicates how MinGW ‘<samp><span class="samp">libgcj</span></samp>’ translates between UNICODE 1442characters and the Win32 API. 1443 1444 <br><dt><code>--enable-java-home</code><dd>If enabled, this creates a JPackage compatible SDK environment during install. 1445Note that if –enable-java-home is used, –with-arch-directory=ARCH must also 1446be specified. 1447 1448 <br><dt><code>--with-arch-directory=ARCH</code><dd>Specifies the name to use for the <samp><span class="file">jre/lib/ARCH</span></samp> directory in the SDK 1449environment created when –enable-java-home is passed. Typical names for this 1450directory include i386, amd64, ia64, etc. 1451 1452 <br><dt><code>--with-os-directory=DIR</code><dd>Specifies the OS directory for the SDK include directory. This is set to auto 1453detect, and is typically 'linux'. 1454 1455 <br><dt><code>--with-origin-name=NAME</code><dd>Specifies the JPackage origin name. This defaults to the 'gcj' in 1456java-1.5.0-gcj. 1457 1458 <br><dt><code>--with-arch-suffix=SUFFIX</code><dd>Specifies the suffix for the sdk directory. Defaults to the empty string. 1459Examples include '.x86_64' in 'java-1.5.0-gcj-1.5.0.0.x86_64'. 1460 1461 <br><dt><code>--with-jvm-root-dir=DIR</code><dd>Specifies where to install the SDK. Default is $(prefix)/lib/jvm. 1462 1463 <br><dt><code>--with-jvm-jar-dir=DIR</code><dd>Specifies where to install jars. Default is $(prefix)/lib/jvm-exports. 1464 1465 <br><dt><code>--with-python-dir=DIR</code><dd>Specifies where to install the Python modules used for aot-compile. DIR should 1466not include the prefix used in installation. For example, if the Python modules 1467are to be installed in /usr/lib/python2.5/site-packages, then 1468–with-python-dir=/lib/python2.5/site-packages should be passed. If this is 1469not specified, then the Python modules are installed in $(prefix)/share/python. 1470 1471 <br><dt><code>--enable-aot-compile-rpm</code><dd>Adds aot-compile-rpm to the list of installed scripts. 1472 1473 <br><dt><code>--enable-browser-plugin</code><dd>Build the gcjwebplugin web browser plugin. 1474 1475 <br><dt><code>--enable-static-libjava</code><dd>Build static libraries in libjava. The default is to only build shared 1476libraries. 1477 1478 <dl> 1479<dt><code>ansi</code><dd>Use the single-byte <code>char</code> and the Win32 A functions natively, 1480translating to and from UNICODE when using these functions. If 1481unspecified, this is the default. 1482 1483 <br><dt><code>unicows</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Adds 1484<code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp> to link with ‘<samp><span class="samp">libunicows</span></samp>’. 1485<samp><span class="file">unicows.dll</span></samp> needs to be deployed on Microsoft Windows 9X machines 1486running built executables. <samp><span class="file">libunicows.a</span></samp>, an open-source 1487import library around Microsoft's <code>unicows.dll</code>, is obtained from 1488<a href="http://libunicows.sourceforge.net/">http://libunicows.sourceforge.net/</a>, which also gives details 1489on getting <samp><span class="file">unicows.dll</span></samp> from Microsoft. 1490 1491 <br><dt><code>unicode</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively. Does <em>not</em> 1492add <code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp>. The built executables will 1493only run on Microsoft Windows NT and above. 1494</dl> 1495 </dl> 1496 1497<h5 class="subsubheading"><a name="TOC7"></a>AWT-Specific Options</h5> 1498 1499 <dl> 1500<dt><code>--with-x</code><dd>Use the X Window System. 1501 1502 <br><dt><code>--enable-java-awt=PEER(S)</code><dd>Specifies the AWT peer library or libraries to build alongside 1503‘<samp><span class="samp">libgcj</span></samp>’. If this option is unspecified or disabled, AWT 1504will be non-functional. Current valid values are <samp><span class="option">gtk</span></samp> and 1505<samp><span class="option">xlib</span></samp>. Multiple libraries should be separated by a 1506comma (i.e. <samp><span class="option">--enable-java-awt=gtk,xlib</span></samp>). 1507 1508 <br><dt><code>--enable-gtk-cairo</code><dd>Build the cairo Graphics2D implementation on GTK. 1509 1510 <br><dt><code>--enable-java-gc=TYPE</code><dd>Choose garbage collector. Defaults to <samp><span class="option">boehm</span></samp> if unspecified. 1511 1512 <br><dt><code>--disable-gtktest</code><dd>Do not try to compile and run a test GTK+ program. 1513 1514 <br><dt><code>--disable-glibtest</code><dd>Do not try to compile and run a test GLIB program. 1515 1516 <br><dt><code>--with-libart-prefix=PFX</code><dd>Prefix where libart is installed (optional). 1517 1518 <br><dt><code>--with-libart-exec-prefix=PFX</code><dd>Exec prefix where libart is installed (optional). 1519 1520 <br><dt><code>--disable-libarttest</code><dd>Do not try to compile and run a test libart program. 1521 1522</dl> 1523 1524 <p><hr /> 1525<p><a href="./index.html">Return to the GCC Installation page</a> 1526 1527<!-- ***Building**************************************************************** --> 1528<!-- ***Testing***************************************************************** --> 1529<!-- ***Final install*********************************************************** --> 1530<!-- ***Binaries**************************************************************** --> 1531<!-- ***Specific**************************************************************** --> 1532<!-- ***Old documentation****************************************************** --> 1533<!-- ***GFDL******************************************************************** --> 1534<!-- *************************************************************************** --> 1535<!-- Part 6 The End of the Document --> 1536</body></html> 1537 1538