@c This is for making the `INSTALL' file for the distribution. @c Makeinfo ignores it when processing the file from the include. @setfilename INSTALL @node Installation, Maintenance, Library Summary, Top @appendix Installing the GNU C Library @menu * Tools for Installation:: We recommend using these tools to build. * Supported Configurations:: What systems the GNU C library runs on. * Tips for Installation:: Useful hints for the installation. * Reporting Bugs:: How to report bugs (if you want to get them fixed) and other troubles you may have with the GNU C library. @end menu Installation of the GNU C library is relatively simple, but usually requires several GNU tools to be installed already. @iftex (@pxref{Tools for Installation}, below.) @end iftex Before you do anything else, you should read the file @file{FAQ} found at the top level of the source tree. This file answers common questions and describes problems you may experience with compilation and installation. It is updated more frequently than this manual. To configure the GNU C library for your system, run the shell script @file{configure} with @code{sh}. You might use an argument which is the conventional GNU name for your system configuration---for example, @samp{i486-pc-linux-gnu}, for Linux running on i486. @xref{Installation, Installation, Installing GNU CC, gcc.info, Using and Porting GNU CC}, for a full description of standard GNU configuration names. If you omit the configuration name, @file{configure} will try to guess one for you by inspecting the system it is running on. It may or may not be able to come up with a guess, and the guess might be wrong. @file{configure} will tell you the canonical name of the chosen configuration before proceeding. Here are some options that you should specify (if appropriate) when you run @code{configure}: @table @samp @item --with-binutils=@var{directory} Use the binutils (assembler and linker) in @file{@var{directory}}, not the ones the C compiler would default to. You could use this option if the default binutils on your system cannot deal with all the constructs in the GNU C library. (@code{configure} will detect the problem and suppress these constructs, so the library will still be usable, but functionality may be lost---for example, you can not build a shared libc with old binutils.) @c extra blank line makes it look better @item --without-fp @itemx --nfp Use this option if your computer lacks hardware floating-point support and your operating system does not emulate an FPU. @item --prefix=@var{directory} Install machine-independent data files in subdirectories of @file{@var{directory}}. (You can also set this in @file{configparms}; see below.) The default is to install in `/usr/local'. @item --exec-prefix=@var{directory} Install the library and other machine-dependent files in subdirectories of @file{@var{directory}}. (You can also set this in @file{configparms}; see below.) The default is to use /bin and /sbin. @item --enable-shared @itemx --disable-shared Enable or disable building of an ELF shared library on systems that support it. The default is to build the shared library on systems using ELF when the GNU @code{binutils} are available. @item --enable-profile @itemx --disable-profile Enable or disable building of the profiled C library, @samp{-lc_p}. The default is to build the profiled library. You may wish to disable it if you don't plan to do profiling, because it doubles the build time of compiling just the unprofiled static library. @item --enable-omitfp Enable building a highly-optimized but possibly undebuggable C library. This causes the normal static and shared (if enabled) C libraries to be compiled with maximal optimization, including the @samp{-fomit-frame-pointer} switch that makes debugging impossible on many machines, and without debugging information (which makes the binaries substantially smaller). An additional static library is compiled with no optimization and full debugging information, and installed as @samp{-lc_g}. @item --enable-add-ons[=LIST] Certain components of the C library are distributed separately from the rest of the sources. In particular, the @code{crypt} function and its friends are separated due to US export control regulations, and the threading support code for Linux is maintained separately. You can get these @dfn{add-on} packages from the same place you got the libc sources. To use them, unpack them into your source tree, and give @code{configure} the @samp{--enable-add-ons} option. If you do not wish to use some add-on package that you have present in your source tree, give this option a list of the add-ons that you @emph{do} want used, like this: @samp{--enable-add-ons=crypt,linuxthreads} @end table You should not build the library in the same directory as the sources, because there are bugs in @code{make clean}. Make a directory for the build, and run @code{configure} from that directory, like this: @smallexample mkdir linux cd linux ../configure @end smallexample @noindent @code{configure} looks for the sources in whatever directory you specified for finding @code{configure} itself. It does not matter where in the file system the source and build directories are---as long as you specify the source directory when you run @code{configure}, you will get the proper results. This feature lets you keep sources and binaries in different directories, and that makes it easy to build the library for several different machines from the same set of sources. Simply create a build directory for each target machine, and run @code{configure} in that directory specifying the target machine's configuration name. The library has a number of special-purpose configuration parameters. These are defined in the file @file{configparms}; see the comments in that file for the details. To change them, copy @file{configparms} into your build directory and modify it as appropriate for your system. @code{configure} will not notice your modifications if you change the file in the source directory. It is easy to configure the GNU C library for cross-compilation by setting a few variables in @file{configparms}. Set @code{CC} to the cross-compiler for the target you configured the library for; it is important to use this same @code{CC} value when running @code{configure}, like this: @samp{CC=@var{target}-gcc configure @var{target}}. Set @code{BUILD_CC} to the compiler to use for for programs run on the build system as part of compiling the library. You may need to set @code{AR} and @code{RANLIB} to cross-compiling versions of @code{ar} and @code{ranlib} if the native tools are not configured to work with object files for the target you configured for. Some of the machine-dependent code for some machines uses extensions in the GNU C compiler, so you may need to compile the library with GCC. (In fact, all of the existing complete ports require GCC.) To build the library and related programs, type @code{make}. This will produce a lot of output, some of which may look like errors from @code{make} (but isn't). Look for error messages from @code{make} containing @samp{***}. Those indicate that something is really wrong. To build and run some test programs which exercise some of the library facilities, type @code{make check}. This will produce several files with names like @file{@var{program}.out}. To format the @cite{GNU C Library Reference Manual} for printing, type @w{@code{make dvi}}. You need a working @TeX{} installation to do this. To install the library and its header files, and the Info files of the manual, type @code{make install}. This will build things if necessary, before installing them. If you want to install the files in a different place than the one specified at configuration time you can specify a value for the Makefile variable @code{install_root} on the command line. This is useful to create chroot'ed environment or to prepare binary releases.@refill @node Tools for Installation @appendixsec Recommended Tools to Install the GNU C Library @cindex installation tools @cindex tools, for installing library We recommend installing the following GNU tools before attempting to build the GNU C library: @itemize @bullet @item GNU @code{make} 3.75 You need the latest version of GNU @code{make}. Modifying the GNU C Library to work with other @code{make} programs would be so hard that we recommend you port GNU @code{make} instead. @strong{Really.} We recommend version GNU @code{make} version 3.75. Versions 3.76 and 3.76.1 are known to have bugs which only show up in big projects like GNU @code{libc}. @item GCC 2.8.1/EGCS 1.0.2 On most platforms, the GNU C library can only be compiled with the GNU C compiler family. We recommend GCC version 2.8.1 and EGCS version 1.0.2 or later versions of these two; earlier versions may have problems. @item GNU @code{binutils} 2.8.1.0.23 Using the GNU @code{binutils} (assembler, linker, and related tools) is preferable when possible, and they are required to build an ELF shared C library. Version 2.1 of the library uses ELF symbol versioning extensively. Support for this feature is incomplete or buggy before binutils 2.8.1.0.23, so you must use at least this version. @item GNU @code{texinfo} 3.11 To correctly translate and install the Texinfo documentation you need this version of the @code{texinfo} package. Earlier versions do not understand all the tags used in the document, and the installation mechanisms for the info files is not present or works differently. On some Debian Linux based systems the @code{install-info} program supplied with the system works differently from the one we expect. You must therefore run @code{make install} like this: @smallexample make INSTALL_INFO=/path/to/GNU/install-info install @end smallexample @item GNU @code{awk} 3.0 Several files used during the build are generated using features of GNU @code{awk} that are not found in other implementations. @c XXX: Does mawk work? @end itemize @noindent If you change any of the @file{configure.in} files you will also need @itemize @bullet @item GNU @code{autoconf} 2.12 @end itemize @noindent and if you change any of the message translation files you will need @itemize @bullet @item GNU @code{gettext} 0.10 or later @end itemize @noindent You may also need these packages if you upgrade your source tree using patches, although we try to avoid this. @node Supported Configurations @appendixsec Supported Configurations @cindex configurations, all supported The GNU C Library currently supports configurations that match the following patterns: @smallexample alpha-@var{anything}-linux i@var{x}86-@var{anything}-gnu i@var{x}86-@var{anything}-linux m68k-@var{anything}-linux powerpc-@var{anything}-linux sparc-@var{anything}-linux sparc64-@var{anything}-linux @end smallexample Former releases of this library (version 1.09.1 and perhaps earlier versions) used to run on the following configurations: @smallexample alpha-dec-osf1 alpha-@var{anything}-linuxecoff i@var{x}86-@var{anything}-bsd4.3 i@var{x}86-@var{anything}-isc2.2 i@var{x}86-@var{anything}-isc3.@var{n} i@var{x}86-@var{anything}-sco3.2 i@var{x}86-@var{anything}-sco3.2v4 i@var{x}86-@var{anything}-sysv i@var{x}86-@var{anything}-sysv4 i@var{x}86-force_cpu386-none i@var{x}86-sequent-bsd i960-nindy960-none m68k-hp-bsd4.3 m68k-mvme135-none m68k-mvme136-none m68k-sony-newsos3 m68k-sony-newsos4 m68k-sun-sunos4.@var{n} mips-dec-ultrix4.@var{n} mips-sgi-irix4.@var{n} sparc-sun-solaris2.@var{n} sparc-sun-sunos4.@var{n} @end smallexample Since no one has volunteered to test and fix these configurations, they are not supported at the moment. They probably don't compile; they definitely don't work anymore. Porting the library is not hard. If you are interested in doing a port, please contact the glibc maintainers by sending electronic mail to @email{bug-glibc@@gnu.org}. Each case of @samp{i@var{x}86} can be @samp{i386}, @samp{i486}, @samp{i586}, or @samp{i686}. All of those configurations produce a library that can run on any of these processors. The library will be optimized for the specified processor, but will not use instructions not available on all of them. While no other configurations are supported, there are handy aliases for these few. (These aliases work in other GNU software as well.) @smallexample decstation hp320-bsd4.3 hp300bsd i486-gnu i586-linux i386-sco i386-sco3.2v4 i386-sequent-dynix i386-svr4 news sun3-sunos4.@var{n} sun3 sun4-solaris2.@var{n} sun4-sunos5.@var{n} sun4-sunos4.@var{n} sun4 @end smallexample @node Tips for Installation @appendixsec Useful hints for the installation There are a some more or less obvious methods one should know when compiling GNU libc: @itemize @bullet @item Better never compile in the source directory. Create a new directory and run the @file{configure} from there. Everything should happen automagically. @item You can use the @code{-j} option of GNU make by changing the line specifying @code{PARALLELMAKE} in the Makefile generated during the configuration. It is not useful to start the @code{make} process using the @code{-j} option since this option is not propagated down to the sub-@code{make}s. @item If you made some changes after a complete build and only want to check these changes run @code{make} while specifying the list of subdirs it has to visit. @smallexample make subdirs="nss elf" @end smallexample The above build run will only visit the subdirectories @file{nss} and @file{elf}. Beside this it updates the @file{libc} files itself. @end itemize @node Reporting Bugs @appendixsec Reporting Bugs @cindex reporting bugs @cindex bugs, reporting There are probably bugs in the GNU C library. There are certainly errors and omissions in this manual. If you report them, they will get fixed. If you don't, no one will ever know about them and they will remain unfixed for all eternity, if not longer. To report a bug, first you must find it. Hopefully, this will be the hard part. Once you've found a bug, make sure it's really a bug. A good way to do this is to see if the GNU C library behaves the same way some other C library does. If so, probably you are wrong and the libraries are right (but not necessarily). If not, one of the libraries is probably wrong. Once you're sure you've found a bug, try to narrow it down to the smallest test case that reproduces the problem. In the case of a C library, you really only need to narrow it down to one library function call, if possible. This should not be too difficult. The final step when you have a simple test case is to report the bug. When reporting a bug, send your test case, the results you got, the results you expected, what you think the problem might be (if you've thought of anything), your system type, and the version of the GNU C library which you are using. Also include the files @file{config.status} and @file{config.make} which are created by running @file{configure}; they will be in whatever directory was current when you ran @file{configure}. If you think you have found some way in which the GNU C library does not conform to the ISO and POSIX standards (@pxref{Standards and Portability}), that is definitely a bug. Report it!@refill Send bug reports to the Internet address @email{bug-glibc@@gnu.org} using the @code{glibcbug} script which is installed by the GNU C library. If you have other problems with installation or use, please report those as well.@refill If you are not sure how a function should behave, and this manual doesn't tell you, that's a bug in the manual. Report that too! If the function's behavior disagrees with the manual, then either the library or the manual has a bug, so report the disagreement. If you find any errors or omissions in this manual, please report them to the Internet address @email{bug-glibc-manual@@gnu.org}.