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1 | Installing the GNU C Library |
2 | **************************** | |
41aa20c2 | 3 | |
6a3951a0 | 4 | Before you do anything else, you should read the FAQ at |
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5 | <https://sourceware.org/glibc/wiki/FAQ>. It answers common questions |
6 | and describes problems you may experience with compilation and | |
7 | installation. | |
41aa20c2 | 8 | |
00c1176b | 9 | You will need recent versions of several GNU tools: definitely GCC |
fe959e1e | 10 | and GNU Make, and possibly others. *Note Tools for Compilation::, |
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11 | below. |
12 | ||
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13 | Configuring and compiling the GNU C Library |
14 | =========================================== | |
00c1176b | 15 | |
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16 | The GNU C Library cannot be compiled in the source directory. You must |
17 | build it in a separate build directory. For example, if you have | |
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18 | unpacked the GNU C Library sources in ‘/src/gnu/glibc-VERSION’, create a |
19 | directory ‘/src/gnu/glibc-build’ to put the object files in. This | |
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20 | allows removing the whole build directory in case an error occurs, which |
21 | is the safest way to get a fresh start and should always be done. | |
00c1176b | 22 | |
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23 | From your object directory, run the shell script ‘configure’ located |
24 | at the top level of the source tree. In the scenario above, you’d type | |
00c1176b | 25 | |
f1e86fca | 26 | $ ../glibc-VERSION/configure ARGS... |
00c1176b | 27 | |
84e93afc | 28 | Please note that even though you’re building in a separate build |
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29 | directory, the compilation may need to create or modify files and |
30 | directories in the source directory. | |
f05f5ca3 | 31 | |
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32 | ‘configure’ takes many options, but the only one that is usually |
33 | mandatory is ‘--prefix’. This option tells ‘configure’ where you want | |
34 | the GNU C Library installed. This defaults to ‘/usr/local’, but the | |
1f77f049 | 35 | normal setting to install as the standard system library is |
84e93afc | 36 | ‘--prefix=/usr’ for GNU/Linux systems and ‘--prefix=’ (an empty prefix) |
1f77f049 | 37 | for GNU/Hurd systems. |
00c1176b | 38 | |
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39 | It may also be useful to pass ‘CC=COMPILER’ and ‘CFLAGS=FLAGS’ |
40 | arguments to ‘configure’. ‘CC’ selects the C compiler that will be | |
41 | used, and ‘CFLAGS’ sets optimization options for the compiler. Any | |
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42 | compiler options required for all compilations, such as options |
43 | selecting an ABI or a processor for which to generate code, should be | |
84e93afc | 44 | included in ‘CC’. Options that may be overridden by the GNU C Library |
db9881ec | 45 | build system for particular files, such as for optimization and |
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46 | debugging, should go in ‘CFLAGS’. The default value of ‘CFLAGS’ is ‘-g |
47 | -O2’, and the GNU C Library cannot be compiled without optimization, so | |
48 | if ‘CFLAGS’ is specified it must enable optimization. For example: | |
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49 | |
50 | $ ../glibc-VERSION/configure CC="gcc -m32" CFLAGS="-O3" | |
00c1176b | 51 | |
bd952512 | 52 | The following list describes all of the available options for |
84e93afc | 53 | ‘configure’: |
00c1176b | 54 | |
84e93afc | 55 | ‘--prefix=DIRECTORY’ |
00c1176b | 56 | Install machine-independent data files in subdirectories of |
84e93afc | 57 | ‘DIRECTORY’. The default is to install in ‘/usr/local’. |
00c1176b | 58 | |
84e93afc | 59 | ‘--exec-prefix=DIRECTORY’ |
00c1176b | 60 | Install the library and other machine-dependent files in |
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61 | subdirectories of ‘DIRECTORY’. The default is to the ‘--prefix’ |
62 | directory if that option is specified, or ‘/usr/local’ otherwise. | |
00c1176b | 63 | |
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64 | ‘--with-headers=DIRECTORY’ |
65 | Look for kernel header files in DIRECTORY, not ‘/usr/include’. The | |
66 | GNU C Library needs information from the kernel’s header files | |
1f77f049 | 67 | describing the interface to the kernel. The GNU C Library will |
84e93afc | 68 | normally look in ‘/usr/include’ for them, but if you specify this |
1f77f049 | 69 | option, it will look in DIRECTORY instead. |
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70 | |
71 | This option is primarily of use on a system where the headers in | |
84e93afc | 72 | ‘/usr/include’ come from an older version of the GNU C Library. |
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73 | Conflicts can occasionally happen in this case. You can also use |
74 | this option if you want to compile the GNU C Library with a newer | |
84e93afc | 75 | set of kernel headers than the ones found in ‘/usr/include’. |
41aa20c2 | 76 | |
84e93afc | 77 | ‘--enable-kernel=VERSION’ |
90d1d40b | 78 | This option is currently only useful on GNU/Linux systems. The |
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79 | VERSION parameter should have the form X.Y.Z and describes the |
80 | smallest version of the Linux kernel the generated library is | |
81 | expected to support. The higher the VERSION number is, the less | |
82 | compatibility code is added, and the faster the code gets. | |
83 | ||
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84 | ‘--with-binutils=DIRECTORY’ |
85 | Use the binutils (assembler and linker) in ‘DIRECTORY’, not the | |
6736e93b | 86 | ones the C compiler would default to. You can use this option if |
41aa20c2 | 87 | the default binutils on your system cannot deal with all the |
84e93afc | 88 | constructs in the GNU C Library. In that case, ‘configure’ will |
bd952512 | 89 | detect the problem and suppress these constructs, so that the |
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90 | library will still be usable, but functionality may be lost—for |
91 | example, you can’t build a shared libc with old binutils. | |
41aa20c2 | 92 | |
84e93afc | 93 | ‘--with-nonshared-cflags=CFLAGS’ |
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94 | Use additional compiler flags CFLAGS to build the parts of the |
95 | library which are always statically linked into applications and | |
96 | libraries even with shared linking (that is, the object files | |
84e93afc | 97 | contained in ‘lib*_nonshared.a’ libraries). The build process will |
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98 | automatically use the appropriate flags, but this option can be |
99 | used to set additional flags required for building applications and | |
100 | libraries, to match local policy. For example, if such a policy | |
101 | requires that all code linked into applications must be built with | |
102 | source fortification, | |
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103 | ‘--with-nonshared-cflags=-Wp,-D_FORTIFY_SOURCE=2’ will make sure |
104 | that the objects in ‘libc_nonshared.a’ are compiled with this flag | |
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105 | (although this will not affect the generated code in this |
106 | particular case and potentially change debugging information and | |
107 | metadata only). | |
108 | ||
84e93afc | 109 | ‘--with-rtld-early-cflags=CFLAGS’ |
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110 | Use additional compiler flags CFLAGS to build the early startup |
111 | code of the dynamic linker. These flags can be used to enable | |
112 | early dynamic linker diagnostics to run on CPUs which are not | |
113 | compatible with the rest of the GNU C Library, for example, due to | |
114 | compiler flags which target a later instruction set architecture | |
115 | (ISA). | |
116 | ||
84e93afc | 117 | ‘--with-timeoutfactor=NUM’ |
bada2e31 | 118 | Specify an integer NUM to scale the timeout of test programs. This |
84e93afc | 119 | factor can be changed at run time using ‘TIMEOUTFACTOR’ environment |
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120 | variable. |
121 | ||
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122 | ‘--disable-shared’ |
123 | Don’t build shared libraries even if it is possible. Not all | |
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124 | systems support shared libraries; you need ELF support and |
125 | (currently) the GNU linker. | |
41aa20c2 | 126 | |
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127 | ‘--disable-default-pie’ |
128 | Don’t build glibc programs and the testsuite as position | |
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129 | independent executables (PIE). By default, glibc programs and tests |
130 | are created as position independent executables on targets that | |
131 | support it. If the toolchain and architecture support it, static | |
132 | executables are built as static PIE and the resulting glibc can be | |
133 | used with the GCC option, -static-pie, which is available with GCC | |
134 | 8 or above, to create static PIE. | |
9d7a3741 | 135 | |
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136 | ‘--enable-cet’ |
137 | ‘--enable-cet=permissive’ | |
e6c69509 | 138 | Enable Intel Control-flow Enforcement Technology (CET) support. |
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139 | When the GNU C Library is built with ‘--enable-cet’ or |
140 | ‘--enable-cet=permissive’, the resulting library is protected with | |
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141 | indirect branch tracking (IBT) and shadow stack (SHSTK). When CET |
142 | is enabled, the GNU C Library is compatible with all existing | |
143 | executables and shared libraries. This feature is currently | |
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144 | supported on x86_64 and x32 with GCC 8 and binutils 2.29 or later. |
145 | With ‘--enable-cet’, it is an error to dlopen a non CET enabled | |
146 | shared library in CET enabled application. With | |
147 | ‘--enable-cet=permissive’, CET is disabled when dlopening a non CET | |
148 | enabled shared library in CET enabled application. | |
149 | ||
150 | NOTE: ‘--enable-cet’ has been tested for x86_64 and x32 on non-CET | |
151 | and CET processors. | |
e84bd851 | 152 | |
84e93afc | 153 | ‘--enable-memory-tagging’ |
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154 | Enable memory tagging support if the architecture supports it. |
155 | When the GNU C Library is built with this option then the resulting | |
156 | library will be able to control the use of tagged memory when | |
157 | hardware support is present by use of the tunable | |
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158 | ‘glibc.mem.tagging’. This includes the generation of tagged memory |
159 | when using the ‘malloc’ APIs. | |
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160 | |
161 | At present only AArch64 platforms with MTE provide this | |
162 | functionality, although the library will still operate (without | |
163 | memory tagging) on older versions of the architecture. | |
164 | ||
165 | The default is to disable support for memory tagging. | |
166 | ||
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167 | ‘--disable-profile’ |
168 | Don’t build libraries with profiling information. You may want to | |
169 | use this option if you don’t plan to do profiling. | |
41aa20c2 | 170 | |
84e93afc | 171 | ‘--enable-static-nss’ |
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172 | Compile static versions of the NSS (Name Service Switch) libraries. |
173 | This is not recommended because it defeats the purpose of NSS; a | |
174 | program linked statically with the NSS libraries cannot be | |
175 | dynamically reconfigured to use a different name database. | |
176 | ||
84e93afc | 177 | ‘--enable-hardcoded-path-in-tests’ |
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178 | By default, dynamic tests are linked to run with the installed C |
179 | library. This option hardcodes the newly built C library path in | |
180 | dynamic tests so that they can be invoked directly. | |
181 | ||
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182 | ‘--disable-timezone-tools’ |
183 | By default, timezone related utilities (‘zic’, ‘zdump’, and | |
184 | ‘tzselect’) are installed with the GNU C Library. If you are | |
185 | building these independently (e.g. by using the ‘tzcode’ package), | |
44f826e3 | 186 | then this option will allow disabling the install of these. |
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187 | |
188 | Note that you need to make sure the external tools are kept in sync | |
189 | with the versions that the GNU C Library expects as the data | |
84e93afc | 190 | formats may change over time. Consult the ‘timezone’ subdirectory |
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191 | for more details. |
192 | ||
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193 | ‘--enable-stack-protector’ |
194 | ‘--enable-stack-protector=strong’ | |
195 | ‘--enable-stack-protector=all’ | |
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196 | Compile the C library and all other parts of the glibc package |
197 | (including the threading and math libraries, NSS modules, and | |
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198 | transliteration modules) using the GCC ‘-fstack-protector’, |
199 | ‘-fstack-protector-strong’ or ‘-fstack-protector-all’ options to | |
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200 | detect stack overruns. Only the dynamic linker and a small number |
201 | of routines called directly from assembler are excluded from this | |
202 | protection. | |
203 | ||
84e93afc | 204 | ‘--enable-bind-now’ |
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205 | Disable lazy binding for installed shared objects and programs. |
206 | This provides additional security hardening because it enables full | |
207 | RELRO and a read-only global offset table (GOT), at the cost of | |
208 | slightly increased program load times. | |
2d6ab5df | 209 | |
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210 | ‘--enable-pt_chown’ |
211 | The file ‘pt_chown’ is a helper binary for ‘grantpt’ (*note | |
a8db092e | 212 | Pseudo-Terminals: Allocation.) that is installed setuid root to fix |
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213 | up pseudo-terminal ownership on GNU/Hurd. It is not required on |
214 | GNU/Linux, and the GNU C Library will not use the installed | |
84e93afc | 215 | ‘pt_chown’ program when configured with ‘--enable-pt_chown’. |
a8db092e | 216 | |
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217 | ‘--disable-werror’ |
218 | By default, the GNU C Library is built with ‘-Werror’. If you wish | |
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219 | to build without this option (for example, if building with a newer |
220 | version of GCC than this version of the GNU C Library was tested | |
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221 | with, so new warnings cause the build with ‘-Werror’ to fail), you |
222 | can configure with ‘--disable-werror’. | |
a8db092e | 223 | |
84e93afc | 224 | ‘--disable-mathvec’ |
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225 | By default for x86_64, the GNU C Library is built with the vector |
226 | math library. Use this option to disable the vector math library. | |
21933112 | 227 | |
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228 | ‘--disable-scv’ |
229 | Disable using ‘scv’ instruction for syscalls. All syscalls will | |
230 | use ‘sc’ instead, even if the kernel supports ‘scv’. PowerPC only. | |
ebae2f5a | 231 | |
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232 | ‘--build=BUILD-SYSTEM’ |
233 | ‘--host=HOST-SYSTEM’ | |
a8db092e | 234 | These options are for cross-compiling. If you specify both options |
84e93afc | 235 | and BUILD-SYSTEM is different from HOST-SYSTEM, ‘configure’ will |
a8db092e | 236 | prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be |
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237 | used on HOST-SYSTEM. You’ll probably need the ‘--with-headers’ |
238 | option too, and you may have to override CONFIGURE’s selection of | |
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239 | the compiler and/or binutils. |
240 | ||
84e93afc | 241 | If you only specify ‘--host’, ‘configure’ will prepare for a native |
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242 | compile but use what you specify instead of guessing what your |
243 | system is. This is most useful to change the CPU submodel. For | |
84e93afc | 244 | example, if ‘configure’ guesses your machine as ‘i686-pc-linux-gnu’ |
a8db092e | 245 | but you want to compile a library for 586es, give |
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246 | ‘--host=i586-pc-linux-gnu’ or just ‘--host=i586-linux’ and add the |
247 | appropriate compiler flags (‘-mcpu=i586’ will do the trick) to | |
248 | ‘CC’. | |
1792d4db | 249 | |
84e93afc | 250 | If you specify just ‘--build’, ‘configure’ will get confused. |
41aa20c2 | 251 | |
84e93afc | 252 | ‘--with-pkgversion=VERSION’ |
8b748aed | 253 | Specify a description, possibly including a build number or build |
84e93afc | 254 | date, of the binaries being built, to be included in ‘--version’ |
8b748aed | 255 | output from programs installed with the GNU C Library. For |
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256 | example, ‘--with-pkgversion='FooBar GNU/Linux glibc build 123'’. |
257 | The default value is ‘GNU libc’. | |
8b748aed | 258 | |
84e93afc | 259 | ‘--with-bugurl=URL’ |
8b748aed | 260 | Specify the URL that users should visit if they wish to report a |
84e93afc | 261 | bug, to be included in ‘--help’ output from programs installed with |
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262 | the GNU C Library. The default value refers to the main |
263 | bug-reporting information for the GNU C Library. | |
264 | ||
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265 | ‘--enable-fortify-source’ |
266 | ‘--enable-fortify-source=LEVEL’ | |
267 | Use -D_FORTIFY_SOURCE=‘LEVEL’ to control hardening in the GNU C | |
268 | Library. If not provided, ‘LEVEL’ defaults to highest possible | |
269 | value supported by the build compiler. | |
270 | ||
271 | Default is to disable fortification. | |
272 | ||
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273 | To build the library and related programs, type ‘make’. This will |
274 | produce a lot of output, some of which may look like errors from ‘make’ | |
275 | but aren’t. Look for error messages from ‘make’ containing ‘***’. | |
b55a155f | 276 | Those indicate that something is seriously wrong. |
41aa20c2 | 277 | |
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278 | The compilation process can take a long time, depending on the |
279 | configuration and the speed of your machine. Some complex modules may | |
280 | take a very long time to compile, as much as several minutes on slower | |
281 | machines. Do not panic if the compiler appears to hang. | |
00c1176b | 282 | |
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283 | If you want to run a parallel make, simply pass the ‘-j’ option with |
284 | an appropriate numeric parameter to ‘make’. You need a recent GNU | |
285 | ‘make’ version, though. | |
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286 | |
287 | To build and run test programs which exercise some of the library | |
84e93afc | 288 | facilities, type ‘make check’. If it does not complete successfully, do |
a8db092e | 289 | not use the built library, and report a bug after verifying that the |
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290 | problem is not already known. *Note Reporting Bugs::, for instructions |
291 | on reporting bugs. Note that some of the tests assume they are not | |
84e93afc | 292 | being run by ‘root’. We recommend you compile and test the GNU C |
1f77f049 | 293 | Library as an unprivileged user. |
41aa20c2 | 294 | |
8d4b5a8a | 295 | Before reporting bugs make sure there is no problem with your system. |
6736e93b | 296 | The tests (and later installation) use some pre-existing files of the |
84e93afc | 297 | system such as ‘/etc/passwd’, ‘/etc/nsswitch.conf’ and others. These |
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298 | files must all contain correct and sensible content. |
299 | ||
84e93afc | 300 | Normally, ‘make check’ will run all the tests before reporting all |
d6fe5e58 | 301 | problems found and exiting with error status if any problems occurred. |
84e93afc | 302 | You can specify ‘stop-on-test-failure=y’ when running ‘make check’ to |
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303 | make the test run stop and exit with an error status immediately when a |
304 | failure occurs. | |
305 | ||
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306 | To format the ‘GNU C Library Reference Manual’ for printing, type |
307 | ‘make dvi’. You need a working TeX installation to do this. The | |
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308 | distribution builds the on-line formatted version of the manual, as Info |
309 | files, as part of the build process. You can build them manually with | |
84e93afc | 310 | ‘make info’. |
1792d4db | 311 | |
c0389ee4 | 312 | The library has a number of special-purpose configuration parameters |
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313 | which you can find in ‘Makeconfig’. These can be overwritten with the |
314 | file ‘configparms’. To change them, create a ‘configparms’ in your | |
a8db092e | 315 | build directory and add values as appropriate for your system. The file |
84e93afc | 316 | is included and parsed by ‘make’ and has to follow the conventions for |
a8db092e | 317 | makefiles. |
c0389ee4 | 318 | |
1f77f049 | 319 | It is easy to configure the GNU C Library for cross-compilation by |
84e93afc | 320 | setting a few variables in ‘configparms’. Set ‘CC’ to the |
c0389ee4 | 321 | cross-compiler for the target you configured the library for; it is |
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322 | important to use this same ‘CC’ value when running ‘configure’, like |
323 | this: ‘configure TARGET CC=TARGET-gcc’. Set ‘BUILD_CC’ to the compiler | |
6736e93b | 324 | to use for programs run on the build system as part of compiling the |
84e93afc | 325 | library. You may need to set ‘AR’ to cross-compiling versions of ‘ar’ |
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326 | if the native tools are not configured to work with object files for the |
327 | target you configured for. When cross-compiling the GNU C Library, it | |
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328 | may be tested using ‘make check |
329 | test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"’, where SRCDIR | |
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330 | is the absolute directory name for the main source directory and |
331 | HOSTNAME is the host name of a system that can run the newly built | |
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332 | binaries of the GNU C Library. The source and build directories must be |
333 | visible at the same locations on both the build system and HOSTNAME. | |
84e93afc | 334 | The ‘cross-test-ssh.sh’ script requires ‘flock’ from ‘util-linux’ to |
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335 | work when GLIBC_TEST_ALLOW_TIME_SETTING environment variable is set. |
336 | ||
337 | It is also possible to execute tests, which require setting the date | |
338 | on the target machine. Following use cases are supported: | |
84e93afc | 339 | • ‘GLIBC_TEST_ALLOW_TIME_SETTING’ is set in the environment in which |
496e36f2 | 340 | eligible tests are executed and have the privilege to run |
84e93afc | 341 | ‘clock_settime’. In this case, nothing prevents those tests from |
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342 | running in parallel, so the caller shall assure that those tests |
343 | are serialized or provide a proper wrapper script for them. | |
344 | ||
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345 | • The ‘cross-test-ssh.sh’ script is used and one passes the |
346 | ‘--allow-time-setting’ flag. In this case, both sets | |
347 | ‘GLIBC_TEST_ALLOW_TIME_SETTING’ and serialization of test execution | |
496e36f2 | 348 | are assured automatically. |
c0389ee4 | 349 | |
84e93afc | 350 | In general, when testing the GNU C Library, ‘test-wrapper’ may be set |
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351 | to the name and arguments of any program to run newly built binaries. |
352 | This program must preserve the arguments to the binary being run, its | |
8540f6d2 | 353 | working directory and the standard input, output and error file |
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354 | descriptors. If ‘TEST-WRAPPER env’ will not work to run a program with |
355 | environment variables set, then ‘test-wrapper-env’ must be set to a | |
8540f6d2 | 356 | program that runs a newly built program with environment variable |
84e93afc | 357 | assignments in effect, those assignments being specified as ‘VAR=VALUE’ |
8540f6d2 | 358 | before the name of the program to be run. If multiple assignments to |
a8db092e | 359 | the same variable are specified, the last assignment specified must take |
84e93afc | 360 | precedence. Similarly, if ‘TEST-WRAPPER env -i’ will not work to run a |
4acc27ed | 361 | program with an environment completely empty of variables except those |
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362 | directly assigned, then ‘test-wrapper-env-only’ must be set; its use has |
363 | the same syntax as ‘test-wrapper-env’, the only difference in its | |
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364 | semantics being starting with an empty set of environment variables |
365 | rather than the ambient set. | |
0eb69512 | 366 | |
84e93afc | 367 | For AArch64 with SVE, when testing the GNU C Library, ‘test-wrapper’ |
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368 | may be set to "SRCDIR/sysdeps/unix/sysv/linux/aarch64/vltest.py |
369 | VECTOR-LENGTH" to change Vector Length. | |
370 | ||
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371 | Installing the C Library |
372 | ======================== | |
41aa20c2 | 373 | |
80ed68b7 | 374 | To install the library and its header files, and the Info files of the |
84e93afc | 375 | manual, type ‘make install’. This will build things, if necessary, |
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376 | before installing them; however, you should still compile everything |
377 | first. If you are installing the GNU C Library as your primary C | |
378 | library, we recommend that you shut the system down to single-user mode | |
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379 | first, and reboot afterward. This minimizes the risk of breaking things |
380 | when the library changes out from underneath. | |
1792d4db | 381 | |
84e93afc | 382 | ‘make install’ will do the entire job of upgrading from a previous |
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383 | installation of the GNU C Library version 2.x. There may sometimes be |
384 | headers left behind from the previous installation, but those are | |
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385 | generally harmless. If you want to avoid leaving headers behind you can |
386 | do things in the following order. | |
c0389ee4 | 387 | |
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388 | You must first build the library (‘make’), optionally check it (‘make |
389 | check’), switch the include directories and then install (‘make | |
390 | install’). The steps must be done in this order. Not moving the | |
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391 | directory before install will result in an unusable mixture of header |
392 | files from both libraries, but configuring, building, and checking the | |
393 | library requires the ability to compile and run programs against the old | |
84e93afc | 394 | library. The new ‘/usr/include’, after switching the include |
02c4bbad | 395 | directories and before installing the library should contain the Linux |
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396 | headers, but nothing else. If you do this, you will need to restore any |
397 | headers from libraries other than the GNU C Library yourself after | |
1f77f049 | 398 | installing the library. |
c0389ee4 | 399 | |
1f77f049 | 400 | You can install the GNU C Library somewhere other than where you |
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401 | configured it to go by setting the ‘DESTDIR’ GNU standard make variable |
402 | on the command line for ‘make install’. The value of this variable is | |
1f77f049 | 403 | prepended to all the paths for installation. This is useful when |
a8db092e | 404 | setting up a chroot environment or preparing a binary distribution. The |
a82a3db9 | 405 | directory should be specified with an absolute file name. Installing |
84e93afc | 406 | with the ‘prefix’ and ‘exec_prefix’ GNU standard make variables set is |
a82a3db9 | 407 | not supported. |
1792d4db | 408 | |
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409 | The GNU C Library includes a daemon called ‘nscd’, which you may or |
410 | may not want to run. ‘nscd’ caches name service lookups; it can | |
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411 | dramatically improve performance with NIS+, and may help with DNS as |
412 | well. | |
1792d4db | 413 | |
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414 | One auxiliary program, ‘/usr/libexec/pt_chown’, is installed setuid |
415 | ‘root’ if the ‘--enable-pt_chown’ configuration option is used. This | |
416 | program is invoked by the ‘grantpt’ function; it sets the permissions on | |
a8db092e | 417 | a pseudoterminal so it can be used by the calling process. If you are |
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418 | using a Linux kernel with the ‘devpts’ filesystem enabled and mounted at |
419 | ‘/dev/pts’, you don’t need this program. | |
41aa20c2 | 420 | |
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421 | After installation you should configure the timezone and install |
422 | locales for your system. The time zone configuration ensures that your | |
423 | system time matches the time for your current timezone. The locales | |
424 | ensure that the display of information on your system matches the | |
425 | expectations of your language and geographic region. | |
426 | ||
427 | The GNU C Library is able to use two kinds of localization | |
428 | information sources, the first is a locale database named | |
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429 | ‘locale-archive’ which is generally installed as |
430 | ‘/usr/lib/locale/locale-archive’. The locale archive has the benefit of | |
08a5ee14 CD |
431 | taking up less space and being very fast to load, but only if you plan |
432 | to install sixty or more locales. If you plan to install one or two | |
433 | locales you can instead install individual locales into their self-named | |
84e93afc PE |
434 | directories e.g. ‘/usr/lib/locale/en_US.utf8’. For example to install |
435 | the German locale using the character set for UTF-8 with name ‘de_DE’ | |
436 | into the locale archive issue the command ‘localedef -i de_DE -f UTF-8 | |
437 | de_DE’, and to install just the one locale issue the command ‘localedef | |
438 | --no-archive -i de_DE -f UTF-8 de_DE’. To configure all locales that | |
a8db092e | 439 | are supported by the GNU C Library, you can issue from your build |
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440 | directory the command ‘make localedata/install-locales’ to install all |
441 | locales into the locale archive or ‘make | |
442 | localedata/install-locale-files’ to install all locales as files in the | |
08a5ee14 | 443 | default configured locale installation directory (derived from |
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444 | ‘--prefix’ or ‘--localedir’). To install into an alternative system |
445 | root use ‘DESTDIR’ e.g. ‘make localedata/install-locale-files | |
446 | DESTDIR=/opt/glibc’, but note that this does not change the configured | |
08a5ee14 | 447 | prefix. |
a8db092e | 448 | |
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449 | To configure the locally used timezone, set the ‘TZ’ environment |
450 | variable. The script ‘tzselect’ helps you to select the right value. | |
451 | As an example, for Germany, ‘tzselect’ would tell you to use | |
452 | ‘TZ='Europe/Berlin'’. For a system wide installation (the given paths | |
453 | are for an installation with ‘--prefix=/usr’), link the timezone file | |
454 | which is in ‘/usr/share/zoneinfo’ to the file ‘/etc/localtime’. For | |
455 | Germany, you might execute ‘ln -s /usr/share/zoneinfo/Europe/Berlin | |
456 | /etc/localtime’. | |
bd952512 | 457 | |
c9dc3f62 RM |
458 | Recommended Tools for Compilation |
459 | ================================= | |
41aa20c2 | 460 | |
80ed68b7 | 461 | We recommend installing the following GNU tools before attempting to |
1f77f049 | 462 | build the GNU C Library: |
41aa20c2 | 463 | |
84e93afc | 464 | • GNU ‘make’ 4.0 or newer |
41aa20c2 | 465 | |
84e93afc | 466 | As of release time, GNU ‘make’ 4.4 is the newest verified to work |
c14f2e4a | 467 | to build the GNU C Library. |
f650932b | 468 | |
84e93afc | 469 | • GCC 6.2 or newer |
0e7727f7 | 470 | |
4dcbbc3b | 471 | GCC 6.2 or higher is required. In general it is recommended to use |
4863355a JM |
472 | the newest version of the compiler that is known to work for |
473 | building the GNU C Library, as newer compilers usually produce | |
d09871da | 474 | better code. As of release time, GCC 13.2 is the newest compiler |
4863355a | 475 | verified to work to build the GNU C Library. |
91ea72b7 | 476 | |
50545f5a | 477 | For PowerPC 64-bits little-endian (powerpc64le), a GCC version with |
84e93afc PE |
478 | support for ‘-mno-gnu-attribute’, ‘-mabi=ieeelongdouble’, and |
479 | ‘-mabi=ibmlondouble’ is required. Likewise, the compiler must also | |
480 | support passing ‘-mlong-double-128’ with the preceding options. As | |
5c7ccc29 PM |
481 | of release, this implies GCC 7.4 and newer (excepting GCC 7.5.0, |
482 | see GCC PR94200). These additional features are required for | |
483 | building the GNU C Library with support for IEEE long double. | |
50545f5a | 484 | |
ba0ec34c CD |
485 | For ARC architecture builds, GCC 8.3 or higher is needed. |
486 | ||
844b4d8b SL |
487 | For s390x architecture builds, GCC 7.1 or higher is needed (See gcc |
488 | Bug 98269). | |
489 | ||
cd94326a JR |
490 | For AArch64 architecture builds with mathvec enabled, GCC 10 or |
491 | higher is needed due to dependency on arm_sve.h. | |
492 | ||
022dfdce SL |
493 | For multi-arch support it is recommended to use a GCC which has |
494 | been built with support for GNU indirect functions. This ensures | |
495 | that correct debugging information is generated for functions | |
496 | selected by IFUNC resolvers. This support can either be enabled by | |
84e93afc PE |
497 | configuring GCC with ‘--enable-gnu-indirect-function’, or by |
498 | enabling it by default by setting ‘default_gnu_indirect_function’ | |
022dfdce | 499 | variable for a particular architecture in the GCC source file |
84e93afc | 500 | ‘gcc/config.gcc’. |
022dfdce | 501 | |
1f77f049 JM |
502 | You can use whatever compiler you like to compile programs that use |
503 | the GNU C Library. | |
41aa20c2 | 504 | |
90d1d40b RM |
505 | Check the FAQ for any special compiler issues on particular |
506 | platforms. | |
5713a71e | 507 | |
84e93afc | 508 | • GNU ‘binutils’ 2.25 or later |
41aa20c2 | 509 | |
84e93afc | 510 | You must use GNU ‘binutils’ (as and ld) to build the GNU C Library. |
7a49a7d5 | 511 | No other assembler or linker has the necessary functionality at the |
d09871da | 512 | moment. As of release time, GNU ‘binutils’ 2.41 is the newest |
04cb913d | 513 | verified to work to build the GNU C Library. |
41aa20c2 | 514 | |
84e93afc PE |
515 | For PowerPC 64-bits little-endian (powerpc64le), ‘objcopy’ is |
516 | required to support ‘--update-section’. This option requires | |
3a0acbdc PM |
517 | binutils 2.26 or newer. |
518 | ||
84e93afc | 519 | ARC architecture needs ‘binutils’ 2.32 or higher for TLS related |
ba0ec34c CD |
520 | fixes. |
521 | ||
84e93afc | 522 | • GNU ‘texinfo’ 4.7 or later |
41aa20c2 UD |
523 | |
524 | To correctly translate and install the Texinfo documentation you | |
84e93afc | 525 | need this version of the ‘texinfo’ package. Earlier versions do |
41aa20c2 | 526 | not understand all the tags used in the document, and the |
1792d4db | 527 | installation mechanism for the info files is not present or works |
d09871da | 528 | differently. As of release time, ‘texinfo’ 7.0.3 is the newest |
04cb913d | 529 | verified to work to build the GNU C Library. |
41aa20c2 | 530 | |
84e93afc | 531 | • GNU ‘awk’ 3.1.2, or higher |
00c1176b | 532 | |
84e93afc PE |
533 | ‘awk’ is used in several places to generate files. Some ‘gawk’ |
534 | extensions are used, including the ‘asorti’ function, which was | |
535 | introduced in version 3.1.2 of ‘gawk’. As of release time, ‘gawk’ | |
d09871da | 536 | version 5.2.2 is the newest verified to work to build the GNU C |
2c8f75f7 | 537 | Library. |
41aa20c2 | 538 | |
84e93afc | 539 | • GNU ‘bison’ 2.7 or later |
1faaf703 | 540 | |
84e93afc PE |
541 | ‘bison’ is used to generate the ‘yacc’ parser code in the ‘intl’ |
542 | subdirectory. As of release time, ‘bison’ version 3.8.2 is the | |
93493119 | 543 | newest verified to work to build the GNU C Library. |
1faaf703 | 544 | |
84e93afc | 545 | • Perl 5 |
00c1176b | 546 | |
3c1622eb | 547 | Perl is not required, but if present it is used in some tests and |
84e93afc | 548 | the ‘mtrace’ program, to build the GNU C Library manual. As of |
d09871da | 549 | release time ‘perl’ version 5.38.0 is the newest verified to work |
053c52b1 | 550 | to build the GNU C Library. |
41aa20c2 | 551 | |
84e93afc | 552 | • GNU ‘sed’ 3.02 or newer |
c0389ee4 | 553 | |
84e93afc PE |
554 | ‘Sed’ is used in several places to generate files. Most scripts |
555 | work with any version of ‘sed’. As of release time, ‘sed’ version | |
d09871da | 556 | 4.9 is the newest verified to work to build the GNU C Library. |
c0389ee4 | 557 | |
84e93afc | 558 | • Python 3.4 or later |
3c1622eb | 559 | |
c6982f7e | 560 | Python is required to build the GNU C Library. As of release time, |
51990242 CD |
561 | Python 3.11 is the newest verified to work for building and testing |
562 | the GNU C Library. | |
3c1622eb | 563 | |
84e93afc | 564 | • PExpect 4.0 |
3c1622eb JM |
565 | |
566 | The pretty printer tests drive GDB through test programs and | |
84e93afc | 567 | compare its output to the printers’. PExpect is used to capture |
3c1622eb | 568 | the output of GDB, and should be compatible with the Python version |
6415fd2d | 569 | in your system. As of release time PExpect 4.8.0 is the newest |
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570 | verified to work to test the pretty printers. |
571 | ||
3d926546 FW |
572 | • The Python ‘abnf’ module. |
573 | ||
574 | This module is optional and used to verify some ABNF grammars in | |
575 | the manual. Version 2.2.0 has been confirmed to work as expected. | |
576 | A missing ‘abnf’ module does not reduce the test coverage of the | |
577 | library itself. | |
578 | ||
84e93afc | 579 | • GDB 7.8 or later with support for Python 2.7/3.4 or later |
3c1622eb JM |
580 | |
581 | GDB itself needs to be configured with Python support in order to | |
582 | use the pretty printers. Notice that your system having Python | |
84e93afc PE |
583 | available doesn’t imply that GDB supports it, nor that your |
584 | system’s Python and GDB’s have the same version. As of release | |
d09871da | 585 | time GNU ‘debugger’ 13.2 is the newest verified to work to test the |
330c9d0d | 586 | pretty printers. |
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587 | |
588 | Unless Python, PExpect and GDB with Python support are present, the | |
84e93afc | 589 | printer tests will report themselves as ‘UNSUPPORTED’. Notice that |
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590 | some of the printer tests require the GNU C Library to be compiled |
591 | with debugging symbols. | |
592 | ||
84e93afc | 593 | If you change any of the ‘configure.ac’ files you will also need |
0cc70fcf | 594 | |
c6cb8783 | 595 | • GNU ‘autoconf’ 2.71 (exactly) |
41aa20c2 UD |
596 | |
597 | and if you change any of the message translation files you will need | |
598 | ||
84e93afc | 599 | • GNU ‘gettext’ 0.10.36 or later |
41aa20c2 | 600 | |
84e93afc | 601 | As of release time, GNU ‘gettext’ version 0.21.1 is the newest |
f650932b CD |
602 | version verified to work to build the GNU C Library. |
603 | ||
41aa20c2 UD |
604 | You may also need these packages if you upgrade your source tree using |
605 | patches, although we try to avoid this. | |
606 | ||
c9dc3f62 RM |
607 | Specific advice for GNU/Linux systems |
608 | ===================================== | |
80ed68b7 | 609 | |
a7a93d50 | 610 | If you are installing the GNU C Library on GNU/Linux systems, you need |
5b4ecd3f | 611 | to have the header files from a 3.2 or newer kernel around for |
3265f934 MW |
612 | reference. These headers must be installed using ‘make |
613 | headers_install’; the headers present in the kernel source directory are | |
614 | not suitable for direct use by the GNU C Library. You do not need to | |
615 | use that kernel, just have its headers installed where the GNU C Library | |
616 | can access them, referred to here as INSTALL-DIRECTORY. The easiest way | |
617 | to do this is to unpack it in a directory such as | |
618 | ‘/usr/src/linux-VERSION’. In that directory, run ‘make headers_install | |
84e93afc PE |
619 | INSTALL_HDR_PATH=INSTALL-DIRECTORY’. Finally, configure the GNU C |
620 | Library with the option ‘--with-headers=INSTALL-DIRECTORY/include’. Use | |
a8db092e | 621 | the most recent kernel you can get your hands on. (If you are |
1f77f049 | 622 | cross-compiling the GNU C Library, you need to specify |
84e93afc | 623 | ‘ARCH=ARCHITECTURE’ in the ‘make headers_install’ command, where |
1f77f049 | 624 | ARCHITECTURE is the architecture name used by the Linux kernel, such as |
84e93afc | 625 | ‘x86’ or ‘powerpc’.) |
1f77f049 JM |
626 | |
627 | After installing the GNU C Library, you may need to remove or rename | |
84e93afc PE |
628 | directories such as ‘/usr/include/linux’ and ‘/usr/include/asm’, and |
629 | replace them with copies of directories such as ‘linux’ and ‘asm’ from | |
630 | ‘INSTALL-DIRECTORY/include’. All directories present in | |
631 | ‘INSTALL-DIRECTORY/include’ should be copied, except that the GNU C | |
632 | Library provides its own version of ‘/usr/include/scsi’; the files | |
a8db092e | 633 | provided by the kernel should be copied without replacing those provided |
84e93afc | 634 | by the GNU C Library. The ‘linux’, ‘asm’ and ‘asm-generic’ directories |
a8db092e CD |
635 | are required to compile programs using the GNU C Library; the other |
636 | directories describe interfaces to the kernel but are not required if | |
637 | not compiling programs using those interfaces. You do not need to copy | |
638 | kernel headers if you did not specify an alternate kernel header source | |
84e93afc | 639 | using ‘--with-headers’. |
1f77f049 | 640 | |
a7a93d50 | 641 | The Filesystem Hierarchy Standard for GNU/Linux systems expects some |
84e93afc PE |
642 | components of the GNU C Library installation to be in ‘/lib’ and some in |
643 | ‘/usr/lib’. This is handled automatically if you configure the GNU C | |
644 | Library with ‘--prefix=/usr’. If you set some other prefix or allow it | |
645 | to default to ‘/usr/local’, then all the components are installed there. | |
1792d4db | 646 | |
51990242 | 647 | As of release time, Linux version 6.1.5 is the newest stable version |
7a52dfab | 648 | verified to work to build the GNU C Library. |
6415fd2d | 649 | |
c9dc3f62 RM |
650 | Reporting Bugs |
651 | ============== | |
41aa20c2 | 652 | |
1f77f049 | 653 | There are probably bugs in the GNU C Library. There are certainly |
41aa20c2 | 654 | errors and omissions in this manual. If you report them, they will get |
84e93afc | 655 | fixed. If you don’t, no one will ever know about them and they will |
41aa20c2 UD |
656 | remain unfixed for all eternity, if not longer. |
657 | ||
bd952512 | 658 | It is a good idea to verify that the problem has not already been |
84e93afc | 659 | reported. Bugs are documented in two places: The file ‘BUGS’ describes |
8b748aed | 660 | a number of well known bugs and the central GNU C Library bug tracking |
a306c790 | 661 | system has a WWW interface at <https://sourceware.org/bugzilla/>. The |
8b748aed JM |
662 | WWW interface gives you access to open and closed reports. A closed |
663 | report normally includes a patch or a hint on solving the problem. | |
6736e93b | 664 | |
a8db092e | 665 | To report a bug, first you must find it. With any luck, this will be |
84e93afc | 666 | the hard part. Once you’ve found a bug, make sure it’s really a bug. A |
a8db092e CD |
667 | good way to do this is to see if the GNU C Library behaves the same way |
668 | some other C library does. If so, probably you are wrong and the | |
669 | libraries are right (but not necessarily). If not, one of the libraries | |
670 | is probably wrong. It might not be the GNU C Library. Many historical | |
84e93afc | 671 | Unix C libraries permit things that we don’t, such as closing a file |
a8db092e | 672 | twice. |
1792d4db | 673 | |
1f77f049 | 674 | If you think you have found some way in which the GNU C Library does |
1792d4db | 675 | not conform to the ISO and POSIX standards (*note Standards and |
c0389ee4 | 676 | Portability::), that is definitely a bug. Report it! |
41aa20c2 | 677 | |
84e93afc | 678 | Once you’re sure you’ve found a bug, try to narrow it down to the |
41aa20c2 UD |
679 | smallest test case that reproduces the problem. In the case of a C |
680 | library, you really only need to narrow it down to one library function | |
681 | call, if possible. This should not be too difficult. | |
682 | ||
683 | The final step when you have a simple test case is to report the bug. | |
5a82c748 | 684 | Do this at <https://www.gnu.org/software/libc/bugs.html>. |
41aa20c2 UD |
685 | |
686 | If you are not sure how a function should behave, and this manual | |
84e93afc PE |
687 | doesn’t tell you, that’s a bug in the manual. Report that too! If the |
688 | function’s behavior disagrees with the manual, then either the library | |
41aa20c2 | 689 | or the manual has a bug, so report the disagreement. If you find any |
80ed68b7 RM |
690 | errors or omissions in this manual, please report them to the bug |
691 | database. If you refer to specific sections of the manual, please | |
692 | include the section names for easier identification. |