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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 | |
144 | supported on i386, x86_64 and x32 with GCC 8 and binutils 2.29 or | |
145 | later. Note that when CET is enabled, the GNU C Library requires | |
146 | CPUs capable of multi-byte NOPs, like x86-64 processors as well as | |
84e93afc | 147 | Intel Pentium Pro or newer. With ‘--enable-cet’, it is an error to |
9e38f455 | 148 | dlopen a non CET enabled shared library in CET enabled application. |
84e93afc | 149 | With ‘--enable-cet=permissive’, CET is disabled when dlopening a |
9e38f455 | 150 | non CET enabled shared library in CET enabled application. |
e6c69509 | 151 | |
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152 | NOTE: ‘--enable-cet’ has been tested for i686, x86_64 and x32 on |
153 | non-CET processors. ‘--enable-cet’ has been tested for i686, | |
9e38f455 | 154 | x86_64 and x32 on CET processors. |
e84bd851 | 155 | |
84e93afc | 156 | ‘--enable-memory-tagging’ |
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157 | Enable memory tagging support if the architecture supports it. |
158 | When the GNU C Library is built with this option then the resulting | |
159 | library will be able to control the use of tagged memory when | |
160 | hardware support is present by use of the tunable | |
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161 | ‘glibc.mem.tagging’. This includes the generation of tagged memory |
162 | when using the ‘malloc’ APIs. | |
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163 | |
164 | At present only AArch64 platforms with MTE provide this | |
165 | functionality, although the library will still operate (without | |
166 | memory tagging) on older versions of the architecture. | |
167 | ||
168 | The default is to disable support for memory tagging. | |
169 | ||
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170 | ‘--disable-profile’ |
171 | Don’t build libraries with profiling information. You may want to | |
172 | use this option if you don’t plan to do profiling. | |
41aa20c2 | 173 | |
84e93afc | 174 | ‘--enable-static-nss’ |
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175 | Compile static versions of the NSS (Name Service Switch) libraries. |
176 | This is not recommended because it defeats the purpose of NSS; a | |
177 | program linked statically with the NSS libraries cannot be | |
178 | dynamically reconfigured to use a different name database. | |
179 | ||
84e93afc | 180 | ‘--enable-hardcoded-path-in-tests’ |
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181 | By default, dynamic tests are linked to run with the installed C |
182 | library. This option hardcodes the newly built C library path in | |
183 | dynamic tests so that they can be invoked directly. | |
184 | ||
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185 | ‘--disable-timezone-tools’ |
186 | By default, timezone related utilities (‘zic’, ‘zdump’, and | |
187 | ‘tzselect’) are installed with the GNU C Library. If you are | |
188 | building these independently (e.g. by using the ‘tzcode’ package), | |
44f826e3 | 189 | then this option will allow disabling the install of these. |
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190 | |
191 | Note that you need to make sure the external tools are kept in sync | |
192 | with the versions that the GNU C Library expects as the data | |
84e93afc | 193 | formats may change over time. Consult the ‘timezone’ subdirectory |
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194 | for more details. |
195 | ||
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196 | ‘--enable-stack-protector’ |
197 | ‘--enable-stack-protector=strong’ | |
198 | ‘--enable-stack-protector=all’ | |
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199 | Compile the C library and all other parts of the glibc package |
200 | (including the threading and math libraries, NSS modules, and | |
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201 | transliteration modules) using the GCC ‘-fstack-protector’, |
202 | ‘-fstack-protector-strong’ or ‘-fstack-protector-all’ options to | |
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203 | detect stack overruns. Only the dynamic linker and a small number |
204 | of routines called directly from assembler are excluded from this | |
205 | protection. | |
206 | ||
84e93afc | 207 | ‘--enable-bind-now’ |
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208 | Disable lazy binding for installed shared objects and programs. |
209 | This provides additional security hardening because it enables full | |
210 | RELRO and a read-only global offset table (GOT), at the cost of | |
211 | slightly increased program load times. | |
2d6ab5df | 212 | |
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213 | ‘--enable-pt_chown’ |
214 | The file ‘pt_chown’ is a helper binary for ‘grantpt’ (*note | |
a8db092e | 215 | Pseudo-Terminals: Allocation.) that is installed setuid root to fix |
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216 | up pseudo-terminal ownership on GNU/Hurd. It is not required on |
217 | GNU/Linux, and the GNU C Library will not use the installed | |
84e93afc | 218 | ‘pt_chown’ program when configured with ‘--enable-pt_chown’. |
a8db092e | 219 | |
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220 | ‘--disable-werror’ |
221 | By default, the GNU C Library is built with ‘-Werror’. If you wish | |
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222 | to build without this option (for example, if building with a newer |
223 | version of GCC than this version of the GNU C Library was tested | |
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224 | with, so new warnings cause the build with ‘-Werror’ to fail), you |
225 | can configure with ‘--disable-werror’. | |
a8db092e | 226 | |
84e93afc | 227 | ‘--disable-mathvec’ |
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228 | By default for x86_64, the GNU C Library is built with the vector |
229 | math library. Use this option to disable the vector math library. | |
21933112 | 230 | |
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231 | ‘--enable-crypt’ |
232 | Install the legacy passphrase-hashing library ‘libcrypt’ and the | |
233 | header file ‘crypt.h’. ‘unistd.h’ will declare the function | |
234 | ‘crypt’ regardless of this option. Using this option does not | |
235 | change the set of programs that may need to be linked with | |
236 | ‘-lcrypt’; it only means that the GNU C Library will provide that | |
237 | library. | |
238 | ||
239 | This option is for hackers and distributions who may not yet be | |
240 | able to use libcrypt alternatives such as libxcrypt and need this | |
241 | legacy implementation as a temporary workaround. Note that | |
242 | libcrypt may be removed in a future release. | |
e69d994a | 243 | |
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244 | ‘--disable-scv’ |
245 | Disable using ‘scv’ instruction for syscalls. All syscalls will | |
246 | use ‘sc’ instead, even if the kernel supports ‘scv’. PowerPC only. | |
ebae2f5a | 247 | |
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248 | ‘--build=BUILD-SYSTEM’ |
249 | ‘--host=HOST-SYSTEM’ | |
a8db092e | 250 | These options are for cross-compiling. If you specify both options |
84e93afc | 251 | and BUILD-SYSTEM is different from HOST-SYSTEM, ‘configure’ will |
a8db092e | 252 | prepare to cross-compile the GNU C Library from BUILD-SYSTEM to be |
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253 | used on HOST-SYSTEM. You’ll probably need the ‘--with-headers’ |
254 | option too, and you may have to override CONFIGURE’s selection of | |
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255 | the compiler and/or binutils. |
256 | ||
84e93afc | 257 | If you only specify ‘--host’, ‘configure’ will prepare for a native |
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258 | compile but use what you specify instead of guessing what your |
259 | system is. This is most useful to change the CPU submodel. For | |
84e93afc | 260 | example, if ‘configure’ guesses your machine as ‘i686-pc-linux-gnu’ |
a8db092e | 261 | but you want to compile a library for 586es, give |
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262 | ‘--host=i586-pc-linux-gnu’ or just ‘--host=i586-linux’ and add the |
263 | appropriate compiler flags (‘-mcpu=i586’ will do the trick) to | |
264 | ‘CC’. | |
1792d4db | 265 | |
84e93afc | 266 | If you specify just ‘--build’, ‘configure’ will get confused. |
41aa20c2 | 267 | |
84e93afc | 268 | ‘--with-pkgversion=VERSION’ |
8b748aed | 269 | Specify a description, possibly including a build number or build |
84e93afc | 270 | date, of the binaries being built, to be included in ‘--version’ |
8b748aed | 271 | output from programs installed with the GNU C Library. For |
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272 | example, ‘--with-pkgversion='FooBar GNU/Linux glibc build 123'’. |
273 | The default value is ‘GNU libc’. | |
8b748aed | 274 | |
84e93afc | 275 | ‘--with-bugurl=URL’ |
8b748aed | 276 | Specify the URL that users should visit if they wish to report a |
84e93afc | 277 | bug, to be included in ‘--help’ output from programs installed with |
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278 | the GNU C Library. The default value refers to the main |
279 | bug-reporting information for the GNU C Library. | |
280 | ||
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281 | ‘--enable-fortify-source’ |
282 | ‘--enable-fortify-source=LEVEL’ | |
283 | Use -D_FORTIFY_SOURCE=‘LEVEL’ to control hardening in the GNU C | |
284 | Library. If not provided, ‘LEVEL’ defaults to highest possible | |
285 | value supported by the build compiler. | |
286 | ||
287 | Default is to disable fortification. | |
288 | ||
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289 | To build the library and related programs, type ‘make’. This will |
290 | produce a lot of output, some of which may look like errors from ‘make’ | |
291 | but aren’t. Look for error messages from ‘make’ containing ‘***’. | |
b55a155f | 292 | Those indicate that something is seriously wrong. |
41aa20c2 | 293 | |
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294 | The compilation process can take a long time, depending on the |
295 | configuration and the speed of your machine. Some complex modules may | |
296 | take a very long time to compile, as much as several minutes on slower | |
297 | machines. Do not panic if the compiler appears to hang. | |
00c1176b | 298 | |
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299 | If you want to run a parallel make, simply pass the ‘-j’ option with |
300 | an appropriate numeric parameter to ‘make’. You need a recent GNU | |
301 | ‘make’ version, though. | |
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302 | |
303 | To build and run test programs which exercise some of the library | |
84e93afc | 304 | facilities, type ‘make check’. If it does not complete successfully, do |
a8db092e | 305 | not use the built library, and report a bug after verifying that the |
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306 | problem is not already known. *Note Reporting Bugs::, for instructions |
307 | on reporting bugs. Note that some of the tests assume they are not | |
84e93afc | 308 | being run by ‘root’. We recommend you compile and test the GNU C |
1f77f049 | 309 | Library as an unprivileged user. |
41aa20c2 | 310 | |
8d4b5a8a | 311 | Before reporting bugs make sure there is no problem with your system. |
6736e93b | 312 | The tests (and later installation) use some pre-existing files of the |
84e93afc | 313 | system such as ‘/etc/passwd’, ‘/etc/nsswitch.conf’ and others. These |
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314 | files must all contain correct and sensible content. |
315 | ||
84e93afc | 316 | Normally, ‘make check’ will run all the tests before reporting all |
d6fe5e58 | 317 | problems found and exiting with error status if any problems occurred. |
84e93afc | 318 | You can specify ‘stop-on-test-failure=y’ when running ‘make check’ to |
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319 | make the test run stop and exit with an error status immediately when a |
320 | failure occurs. | |
321 | ||
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322 | To format the ‘GNU C Library Reference Manual’ for printing, type |
323 | ‘make dvi’. You need a working TeX installation to do this. The | |
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324 | distribution builds the on-line formatted version of the manual, as Info |
325 | files, as part of the build process. You can build them manually with | |
84e93afc | 326 | ‘make info’. |
1792d4db | 327 | |
c0389ee4 | 328 | The library has a number of special-purpose configuration parameters |
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329 | which you can find in ‘Makeconfig’. These can be overwritten with the |
330 | file ‘configparms’. To change them, create a ‘configparms’ in your | |
a8db092e | 331 | build directory and add values as appropriate for your system. The file |
84e93afc | 332 | is included and parsed by ‘make’ and has to follow the conventions for |
a8db092e | 333 | makefiles. |
c0389ee4 | 334 | |
1f77f049 | 335 | It is easy to configure the GNU C Library for cross-compilation by |
84e93afc | 336 | setting a few variables in ‘configparms’. Set ‘CC’ to the |
c0389ee4 | 337 | cross-compiler for the target you configured the library for; it is |
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338 | important to use this same ‘CC’ value when running ‘configure’, like |
339 | this: ‘configure TARGET CC=TARGET-gcc’. Set ‘BUILD_CC’ to the compiler | |
6736e93b | 340 | to use for programs run on the build system as part of compiling the |
84e93afc | 341 | library. You may need to set ‘AR’ to cross-compiling versions of ‘ar’ |
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342 | if the native tools are not configured to work with object files for the |
343 | target you configured for. When cross-compiling the GNU C Library, it | |
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344 | may be tested using ‘make check |
345 | test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"’, where SRCDIR | |
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346 | is the absolute directory name for the main source directory and |
347 | HOSTNAME is the host name of a system that can run the newly built | |
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348 | binaries of the GNU C Library. The source and build directories must be |
349 | visible at the same locations on both the build system and HOSTNAME. | |
84e93afc | 350 | The ‘cross-test-ssh.sh’ script requires ‘flock’ from ‘util-linux’ to |
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351 | work when GLIBC_TEST_ALLOW_TIME_SETTING environment variable is set. |
352 | ||
353 | It is also possible to execute tests, which require setting the date | |
354 | on the target machine. Following use cases are supported: | |
84e93afc | 355 | • ‘GLIBC_TEST_ALLOW_TIME_SETTING’ is set in the environment in which |
496e36f2 | 356 | eligible tests are executed and have the privilege to run |
84e93afc | 357 | ‘clock_settime’. In this case, nothing prevents those tests from |
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358 | running in parallel, so the caller shall assure that those tests |
359 | are serialized or provide a proper wrapper script for them. | |
360 | ||
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361 | • The ‘cross-test-ssh.sh’ script is used and one passes the |
362 | ‘--allow-time-setting’ flag. In this case, both sets | |
363 | ‘GLIBC_TEST_ALLOW_TIME_SETTING’ and serialization of test execution | |
496e36f2 | 364 | are assured automatically. |
c0389ee4 | 365 | |
84e93afc | 366 | In general, when testing the GNU C Library, ‘test-wrapper’ may be set |
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367 | to the name and arguments of any program to run newly built binaries. |
368 | This program must preserve the arguments to the binary being run, its | |
8540f6d2 | 369 | working directory and the standard input, output and error file |
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370 | descriptors. If ‘TEST-WRAPPER env’ will not work to run a program with |
371 | environment variables set, then ‘test-wrapper-env’ must be set to a | |
8540f6d2 | 372 | program that runs a newly built program with environment variable |
84e93afc | 373 | assignments in effect, those assignments being specified as ‘VAR=VALUE’ |
8540f6d2 | 374 | before the name of the program to be run. If multiple assignments to |
a8db092e | 375 | the same variable are specified, the last assignment specified must take |
84e93afc | 376 | precedence. Similarly, if ‘TEST-WRAPPER env -i’ will not work to run a |
4acc27ed | 377 | program with an environment completely empty of variables except those |
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378 | directly assigned, then ‘test-wrapper-env-only’ must be set; its use has |
379 | the same syntax as ‘test-wrapper-env’, the only difference in its | |
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380 | semantics being starting with an empty set of environment variables |
381 | rather than the ambient set. | |
0eb69512 | 382 | |
84e93afc | 383 | For AArch64 with SVE, when testing the GNU C Library, ‘test-wrapper’ |
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384 | may be set to "SRCDIR/sysdeps/unix/sysv/linux/aarch64/vltest.py |
385 | VECTOR-LENGTH" to change Vector Length. | |
386 | ||
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387 | Installing the C Library |
388 | ======================== | |
41aa20c2 | 389 | |
80ed68b7 | 390 | To install the library and its header files, and the Info files of the |
84e93afc | 391 | manual, type ‘make install’. This will build things, if necessary, |
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392 | before installing them; however, you should still compile everything |
393 | first. If you are installing the GNU C Library as your primary C | |
394 | library, we recommend that you shut the system down to single-user mode | |
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395 | first, and reboot afterward. This minimizes the risk of breaking things |
396 | when the library changes out from underneath. | |
1792d4db | 397 | |
84e93afc | 398 | ‘make install’ will do the entire job of upgrading from a previous |
1f77f049 JM |
399 | installation of the GNU C Library version 2.x. There may sometimes be |
400 | headers left behind from the previous installation, but those are | |
a8db092e CD |
401 | generally harmless. If you want to avoid leaving headers behind you can |
402 | do things in the following order. | |
c0389ee4 | 403 | |
84e93afc PE |
404 | You must first build the library (‘make’), optionally check it (‘make |
405 | check’), switch the include directories and then install (‘make | |
406 | install’). The steps must be done in this order. Not moving the | |
c0389ee4 AJ |
407 | directory before install will result in an unusable mixture of header |
408 | files from both libraries, but configuring, building, and checking the | |
409 | library requires the ability to compile and run programs against the old | |
84e93afc | 410 | library. The new ‘/usr/include’, after switching the include |
02c4bbad | 411 | directories and before installing the library should contain the Linux |
a8db092e CD |
412 | headers, but nothing else. If you do this, you will need to restore any |
413 | headers from libraries other than the GNU C Library yourself after | |
1f77f049 | 414 | installing the library. |
c0389ee4 | 415 | |
1f77f049 | 416 | You can install the GNU C Library somewhere other than where you |
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417 | configured it to go by setting the ‘DESTDIR’ GNU standard make variable |
418 | on the command line for ‘make install’. The value of this variable is | |
1f77f049 | 419 | prepended to all the paths for installation. This is useful when |
a8db092e | 420 | setting up a chroot environment or preparing a binary distribution. The |
a82a3db9 | 421 | directory should be specified with an absolute file name. Installing |
84e93afc | 422 | with the ‘prefix’ and ‘exec_prefix’ GNU standard make variables set is |
a82a3db9 | 423 | not supported. |
1792d4db | 424 | |
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425 | The GNU C Library includes a daemon called ‘nscd’, which you may or |
426 | may not want to run. ‘nscd’ caches name service lookups; it can | |
1f77f049 JM |
427 | dramatically improve performance with NIS+, and may help with DNS as |
428 | well. | |
1792d4db | 429 | |
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430 | One auxiliary program, ‘/usr/libexec/pt_chown’, is installed setuid |
431 | ‘root’ if the ‘--enable-pt_chown’ configuration option is used. This | |
432 | program is invoked by the ‘grantpt’ function; it sets the permissions on | |
a8db092e | 433 | a pseudoterminal so it can be used by the calling process. If you are |
84e93afc PE |
434 | using a Linux kernel with the ‘devpts’ filesystem enabled and mounted at |
435 | ‘/dev/pts’, you don’t need this program. | |
41aa20c2 | 436 | |
08a5ee14 CD |
437 | After installation you should configure the timezone and install |
438 | locales for your system. The time zone configuration ensures that your | |
439 | system time matches the time for your current timezone. The locales | |
440 | ensure that the display of information on your system matches the | |
441 | expectations of your language and geographic region. | |
442 | ||
443 | The GNU C Library is able to use two kinds of localization | |
444 | information sources, the first is a locale database named | |
84e93afc PE |
445 | ‘locale-archive’ which is generally installed as |
446 | ‘/usr/lib/locale/locale-archive’. The locale archive has the benefit of | |
08a5ee14 CD |
447 | taking up less space and being very fast to load, but only if you plan |
448 | to install sixty or more locales. If you plan to install one or two | |
449 | locales you can instead install individual locales into their self-named | |
84e93afc PE |
450 | directories e.g. ‘/usr/lib/locale/en_US.utf8’. For example to install |
451 | the German locale using the character set for UTF-8 with name ‘de_DE’ | |
452 | into the locale archive issue the command ‘localedef -i de_DE -f UTF-8 | |
453 | de_DE’, and to install just the one locale issue the command ‘localedef | |
454 | --no-archive -i de_DE -f UTF-8 de_DE’. To configure all locales that | |
a8db092e | 455 | are supported by the GNU C Library, you can issue from your build |
84e93afc PE |
456 | directory the command ‘make localedata/install-locales’ to install all |
457 | locales into the locale archive or ‘make | |
458 | localedata/install-locale-files’ to install all locales as files in the | |
08a5ee14 | 459 | default configured locale installation directory (derived from |
84e93afc PE |
460 | ‘--prefix’ or ‘--localedir’). To install into an alternative system |
461 | root use ‘DESTDIR’ e.g. ‘make localedata/install-locale-files | |
462 | DESTDIR=/opt/glibc’, but note that this does not change the configured | |
08a5ee14 | 463 | prefix. |
a8db092e | 464 | |
84e93afc PE |
465 | To configure the locally used timezone, set the ‘TZ’ environment |
466 | variable. The script ‘tzselect’ helps you to select the right value. | |
467 | As an example, for Germany, ‘tzselect’ would tell you to use | |
468 | ‘TZ='Europe/Berlin'’. For a system wide installation (the given paths | |
469 | are for an installation with ‘--prefix=/usr’), link the timezone file | |
470 | which is in ‘/usr/share/zoneinfo’ to the file ‘/etc/localtime’. For | |
471 | Germany, you might execute ‘ln -s /usr/share/zoneinfo/Europe/Berlin | |
472 | /etc/localtime’. | |
bd952512 | 473 | |
c9dc3f62 RM |
474 | Recommended Tools for Compilation |
475 | ================================= | |
41aa20c2 | 476 | |
80ed68b7 | 477 | We recommend installing the following GNU tools before attempting to |
1f77f049 | 478 | build the GNU C Library: |
41aa20c2 | 479 | |
84e93afc | 480 | • GNU ‘make’ 4.0 or newer |
41aa20c2 | 481 | |
84e93afc | 482 | As of release time, GNU ‘make’ 4.4 is the newest verified to work |
c14f2e4a | 483 | to build the GNU C Library. |
f650932b | 484 | |
84e93afc | 485 | • GCC 6.2 or newer |
0e7727f7 | 486 | |
4dcbbc3b | 487 | GCC 6.2 or higher is required. In general it is recommended to use |
4863355a JM |
488 | the newest version of the compiler that is known to work for |
489 | building the GNU C Library, as newer compilers usually produce | |
51990242 | 490 | better code. As of release time, GCC 13.0 is the newest compiler |
4863355a | 491 | verified to work to build the GNU C Library. |
91ea72b7 | 492 | |
50545f5a | 493 | For PowerPC 64-bits little-endian (powerpc64le), a GCC version with |
84e93afc PE |
494 | support for ‘-mno-gnu-attribute’, ‘-mabi=ieeelongdouble’, and |
495 | ‘-mabi=ibmlondouble’ is required. Likewise, the compiler must also | |
496 | support passing ‘-mlong-double-128’ with the preceding options. As | |
5c7ccc29 PM |
497 | of release, this implies GCC 7.4 and newer (excepting GCC 7.5.0, |
498 | see GCC PR94200). These additional features are required for | |
499 | building the GNU C Library with support for IEEE long double. | |
50545f5a | 500 | |
ba0ec34c CD |
501 | For ARC architecture builds, GCC 8.3 or higher is needed. |
502 | ||
844b4d8b SL |
503 | For s390x architecture builds, GCC 7.1 or higher is needed (See gcc |
504 | Bug 98269). | |
505 | ||
cd94326a JR |
506 | For AArch64 architecture builds with mathvec enabled, GCC 10 or |
507 | higher is needed due to dependency on arm_sve.h. | |
508 | ||
022dfdce SL |
509 | For multi-arch support it is recommended to use a GCC which has |
510 | been built with support for GNU indirect functions. This ensures | |
511 | that correct debugging information is generated for functions | |
512 | selected by IFUNC resolvers. This support can either be enabled by | |
84e93afc PE |
513 | configuring GCC with ‘--enable-gnu-indirect-function’, or by |
514 | enabling it by default by setting ‘default_gnu_indirect_function’ | |
022dfdce | 515 | variable for a particular architecture in the GCC source file |
84e93afc | 516 | ‘gcc/config.gcc’. |
022dfdce | 517 | |
1f77f049 JM |
518 | You can use whatever compiler you like to compile programs that use |
519 | the GNU C Library. | |
41aa20c2 | 520 | |
90d1d40b RM |
521 | Check the FAQ for any special compiler issues on particular |
522 | platforms. | |
5713a71e | 523 | |
84e93afc | 524 | • GNU ‘binutils’ 2.25 or later |
41aa20c2 | 525 | |
84e93afc | 526 | You must use GNU ‘binutils’ (as and ld) to build the GNU C Library. |
7a49a7d5 | 527 | No other assembler or linker has the necessary functionality at the |
84e93afc | 528 | moment. As of release time, GNU ‘binutils’ 2.39 is the newest |
04cb913d | 529 | verified to work to build the GNU C Library. |
41aa20c2 | 530 | |
84e93afc PE |
531 | For PowerPC 64-bits little-endian (powerpc64le), ‘objcopy’ is |
532 | required to support ‘--update-section’. This option requires | |
3a0acbdc PM |
533 | binutils 2.26 or newer. |
534 | ||
84e93afc | 535 | ARC architecture needs ‘binutils’ 2.32 or higher for TLS related |
ba0ec34c CD |
536 | fixes. |
537 | ||
84e93afc | 538 | • GNU ‘texinfo’ 4.7 or later |
41aa20c2 UD |
539 | |
540 | To correctly translate and install the Texinfo documentation you | |
84e93afc | 541 | need this version of the ‘texinfo’ package. Earlier versions do |
41aa20c2 | 542 | not understand all the tags used in the document, and the |
1792d4db | 543 | installation mechanism for the info files is not present or works |
84e93afc | 544 | differently. As of release time, ‘texinfo’ 7.0.2 is the newest |
04cb913d | 545 | verified to work to build the GNU C Library. |
41aa20c2 | 546 | |
84e93afc | 547 | • GNU ‘awk’ 3.1.2, or higher |
00c1176b | 548 | |
84e93afc PE |
549 | ‘awk’ is used in several places to generate files. Some ‘gawk’ |
550 | extensions are used, including the ‘asorti’ function, which was | |
551 | introduced in version 3.1.2 of ‘gawk’. As of release time, ‘gawk’ | |
6415fd2d | 552 | version 5.1.1 is the newest verified to work to build the GNU C |
2c8f75f7 | 553 | Library. |
41aa20c2 | 554 | |
84e93afc | 555 | • GNU ‘bison’ 2.7 or later |
1faaf703 | 556 | |
84e93afc PE |
557 | ‘bison’ is used to generate the ‘yacc’ parser code in the ‘intl’ |
558 | subdirectory. As of release time, ‘bison’ version 3.8.2 is the | |
93493119 | 559 | newest verified to work to build the GNU C Library. |
1faaf703 | 560 | |
84e93afc | 561 | • Perl 5 |
00c1176b | 562 | |
3c1622eb | 563 | Perl is not required, but if present it is used in some tests and |
84e93afc PE |
564 | the ‘mtrace’ program, to build the GNU C Library manual. As of |
565 | release time ‘perl’ version 5.36.0 is the newest verified to work | |
053c52b1 | 566 | to build the GNU C Library. |
41aa20c2 | 567 | |
84e93afc | 568 | • GNU ‘sed’ 3.02 or newer |
c0389ee4 | 569 | |
84e93afc PE |
570 | ‘Sed’ is used in several places to generate files. Most scripts |
571 | work with any version of ‘sed’. As of release time, ‘sed’ version | |
ad477489 | 572 | 4.8 is the newest verified to work to build the GNU C Library. |
c0389ee4 | 573 | |
84e93afc | 574 | • Python 3.4 or later |
3c1622eb | 575 | |
c6982f7e | 576 | Python is required to build the GNU C Library. As of release time, |
51990242 CD |
577 | Python 3.11 is the newest verified to work for building and testing |
578 | the GNU C Library. | |
3c1622eb | 579 | |
84e93afc | 580 | • PExpect 4.0 |
3c1622eb JM |
581 | |
582 | The pretty printer tests drive GDB through test programs and | |
84e93afc | 583 | compare its output to the printers’. PExpect is used to capture |
3c1622eb | 584 | the output of GDB, and should be compatible with the Python version |
6415fd2d | 585 | in your system. As of release time PExpect 4.8.0 is the newest |
3c1622eb JM |
586 | verified to work to test the pretty printers. |
587 | ||
84e93afc | 588 | • GDB 7.8 or later with support for Python 2.7/3.4 or later |
3c1622eb JM |
589 | |
590 | GDB itself needs to be configured with Python support in order to | |
591 | use the pretty printers. Notice that your system having Python | |
84e93afc PE |
592 | available doesn’t imply that GDB supports it, nor that your |
593 | system’s Python and GDB’s have the same version. As of release | |
594 | time GNU ‘debugger’ 12.1 is the newest verified to work to test the | |
330c9d0d | 595 | pretty printers. |
3c1622eb JM |
596 | |
597 | Unless Python, PExpect and GDB with Python support are present, the | |
84e93afc | 598 | printer tests will report themselves as ‘UNSUPPORTED’. Notice that |
3c1622eb JM |
599 | some of the printer tests require the GNU C Library to be compiled |
600 | with debugging symbols. | |
601 | ||
84e93afc | 602 | If you change any of the ‘configure.ac’ files you will also need |
0cc70fcf | 603 | |
c6cb8783 | 604 | • GNU ‘autoconf’ 2.71 (exactly) |
41aa20c2 UD |
605 | |
606 | and if you change any of the message translation files you will need | |
607 | ||
84e93afc | 608 | • GNU ‘gettext’ 0.10.36 or later |
41aa20c2 | 609 | |
84e93afc | 610 | As of release time, GNU ‘gettext’ version 0.21.1 is the newest |
f650932b CD |
611 | version verified to work to build the GNU C Library. |
612 | ||
41aa20c2 UD |
613 | You may also need these packages if you upgrade your source tree using |
614 | patches, although we try to avoid this. | |
615 | ||
c9dc3f62 RM |
616 | Specific advice for GNU/Linux systems |
617 | ===================================== | |
80ed68b7 | 618 | |
a7a93d50 | 619 | If you are installing the GNU C Library on GNU/Linux systems, you need |
5b4ecd3f | 620 | to have the header files from a 3.2 or newer kernel around for |
e9203023 | 621 | reference. (For the ia64 architecture, you need version 3.2.18 or newer |
84e93afc PE |
622 | because this is the first version with support for the ‘accept4’ system |
623 | call.) These headers must be installed using ‘make headers_install’; | |
e9203023 FW |
624 | the headers present in the kernel source directory are not suitable for |
625 | direct use by the GNU C Library. You do not need to use that kernel, | |
626 | just have its headers installed where the GNU C Library can access them, | |
627 | referred to here as INSTALL-DIRECTORY. The easiest way to do this is to | |
84e93afc PE |
628 | unpack it in a directory such as ‘/usr/src/linux-VERSION’. In that |
629 | directory, run ‘make headers_install | |
630 | INSTALL_HDR_PATH=INSTALL-DIRECTORY’. Finally, configure the GNU C | |
631 | Library with the option ‘--with-headers=INSTALL-DIRECTORY/include’. Use | |
a8db092e | 632 | the most recent kernel you can get your hands on. (If you are |
1f77f049 | 633 | cross-compiling the GNU C Library, you need to specify |
84e93afc | 634 | ‘ARCH=ARCHITECTURE’ in the ‘make headers_install’ command, where |
1f77f049 | 635 | ARCHITECTURE is the architecture name used by the Linux kernel, such as |
84e93afc | 636 | ‘x86’ or ‘powerpc’.) |
1f77f049 JM |
637 | |
638 | After installing the GNU C Library, you may need to remove or rename | |
84e93afc PE |
639 | directories such as ‘/usr/include/linux’ and ‘/usr/include/asm’, and |
640 | replace them with copies of directories such as ‘linux’ and ‘asm’ from | |
641 | ‘INSTALL-DIRECTORY/include’. All directories present in | |
642 | ‘INSTALL-DIRECTORY/include’ should be copied, except that the GNU C | |
643 | Library provides its own version of ‘/usr/include/scsi’; the files | |
a8db092e | 644 | provided by the kernel should be copied without replacing those provided |
84e93afc | 645 | by the GNU C Library. The ‘linux’, ‘asm’ and ‘asm-generic’ directories |
a8db092e CD |
646 | are required to compile programs using the GNU C Library; the other |
647 | directories describe interfaces to the kernel but are not required if | |
648 | not compiling programs using those interfaces. You do not need to copy | |
649 | kernel headers if you did not specify an alternate kernel header source | |
84e93afc | 650 | using ‘--with-headers’. |
1f77f049 | 651 | |
a7a93d50 | 652 | The Filesystem Hierarchy Standard for GNU/Linux systems expects some |
84e93afc PE |
653 | components of the GNU C Library installation to be in ‘/lib’ and some in |
654 | ‘/usr/lib’. This is handled automatically if you configure the GNU C | |
655 | Library with ‘--prefix=/usr’. If you set some other prefix or allow it | |
656 | to default to ‘/usr/local’, then all the components are installed there. | |
1792d4db | 657 | |
51990242 | 658 | As of release time, Linux version 6.1.5 is the newest stable version |
7a52dfab | 659 | verified to work to build the GNU C Library. |
6415fd2d | 660 | |
c9dc3f62 RM |
661 | Reporting Bugs |
662 | ============== | |
41aa20c2 | 663 | |
1f77f049 | 664 | There are probably bugs in the GNU C Library. There are certainly |
41aa20c2 | 665 | errors and omissions in this manual. If you report them, they will get |
84e93afc | 666 | fixed. If you don’t, no one will ever know about them and they will |
41aa20c2 UD |
667 | remain unfixed for all eternity, if not longer. |
668 | ||
bd952512 | 669 | It is a good idea to verify that the problem has not already been |
84e93afc | 670 | reported. Bugs are documented in two places: The file ‘BUGS’ describes |
8b748aed | 671 | a number of well known bugs and the central GNU C Library bug tracking |
a306c790 | 672 | system has a WWW interface at <https://sourceware.org/bugzilla/>. The |
8b748aed JM |
673 | WWW interface gives you access to open and closed reports. A closed |
674 | report normally includes a patch or a hint on solving the problem. | |
6736e93b | 675 | |
a8db092e | 676 | To report a bug, first you must find it. With any luck, this will be |
84e93afc | 677 | the hard part. Once you’ve found a bug, make sure it’s really a bug. A |
a8db092e CD |
678 | good way to do this is to see if the GNU C Library behaves the same way |
679 | some other C library does. If so, probably you are wrong and the | |
680 | libraries are right (but not necessarily). If not, one of the libraries | |
681 | is probably wrong. It might not be the GNU C Library. Many historical | |
84e93afc | 682 | Unix C libraries permit things that we don’t, such as closing a file |
a8db092e | 683 | twice. |
1792d4db | 684 | |
1f77f049 | 685 | If you think you have found some way in which the GNU C Library does |
1792d4db | 686 | not conform to the ISO and POSIX standards (*note Standards and |
c0389ee4 | 687 | Portability::), that is definitely a bug. Report it! |
41aa20c2 | 688 | |
84e93afc | 689 | Once you’re sure you’ve found a bug, try to narrow it down to the |
41aa20c2 UD |
690 | smallest test case that reproduces the problem. In the case of a C |
691 | library, you really only need to narrow it down to one library function | |
692 | call, if possible. This should not be too difficult. | |
693 | ||
694 | The final step when you have a simple test case is to report the bug. | |
5a82c748 | 695 | Do this at <https://www.gnu.org/software/libc/bugs.html>. |
41aa20c2 UD |
696 | |
697 | If you are not sure how a function should behave, and this manual | |
84e93afc PE |
698 | doesn’t tell you, that’s a bug in the manual. Report that too! If the |
699 | function’s behavior disagrees with the manual, then either the library | |
41aa20c2 | 700 | or the manual has a bug, so report the disagreement. If you find any |
80ed68b7 RM |
701 | errors or omissions in this manual, please report them to the bug |
702 | database. If you refer to specific sections of the manual, please | |
703 | include the section names for easier identification. |