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How to Install the GNU C Library

Installation of the GNU C library is relatively simple.

You need the latest version of GNU make. Modifying the GNU C Library to work with other make programs would be so hard that we recommend you port GNU make instead. Really.

To configure the GNU C library for your system, run the shell script `configure' with sh. Use an argument which is the conventional GNU name for your system configuration--for example, `sparc-sun-sunos4.1', for a Sun 4 running Sunos 4.1. See section `Installing GNU CC' in Using and Porting GNU CC, for a full description of standard GNU configuration names. If you omit the configuration name, `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 its guess might be wrong. `configure' will tell you the canonical name of the chosen configuration before proceeding.

The GNU C Library currently supports configurations that match the following patterns:


While no other configurations are supported, there are handy aliases for these few. (These aliases work in other GNU software as well.)

hp320-bsd4.3 hp300bsd
sun3-sunos4.n sun3
sun4-solaris2.n sun4-sunos5.n
sun4-sunos4.n sun4

Here are some options that you should specify (if appropriate) when you run configure:

Use this option if you plan to use GNU ld to link programs with the GNU C Library. (We strongly recommend that you do.)

Use this option if you plan to use the GNU assembler, gas, when building the GNU C Library. On some systems, the library may not build properly if you do not use gas.


Use this option if your computer lacks hardware floating point support.

Install machine-independent data files in subdirectories of `directory'. (You can also set this in `configparms'; see below.)

Install the library and other machine-dependent files in subdirectories of `directory'. (You can also set this in `configparms'; see below.)

The simplest way to run configure is to do it in the directory that contains the library sources. This prepares to build the library in that very directory.

You can prepare to build the library in some other directory by going to that other directory to run configure. In order to run configure, you will have to specify a directory for it, like this:

mkdir ../hp320
cd ../hp320
../src/configure hp320-bsd4.3

configure looks for the sources in whatever directory you specified for finding 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 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 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 `Makeconfig'; see the comments in that file for the details.

But don't edit the file `Makeconfig' yourself--instead, create a file `configparms' in the directory where you are building the library, and define in that file the parameters you want to specify. `configparms' should not be an edited copy of `Makeconfig'; specify only the parameters that you want to override.

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.)

The current release of the C library contains some header files that the compiler normally provides: `stddef.h', `stdarg.h', and several files with names of the form `va-machine.h'. The versions of these files that came with older releases of GCC do not work properly with the GNU C library. The `stddef.h' file in release 2.2 and later of GCC is correct. If you have release 2.2 or later of GCC, use its version of `stddef.h' instead of the C library's. To do this, put the line `override stddef.h =' in `configparms'. The other files are corrected in release 2.3 and later of GCC. `configure' will automatically detect whether the installed `stdarg.h' and `va-machine.h' files are compatible with the C library, and use its own if not.

There is a potential problem with the size_t type and versions of GCC prior to release 2.4. ANSI C requires that size_t always be an unsigned type. For compatibility with existing systems' header files, GCC defines size_t in `stddef.h' to be whatever type the system's `sys/types.h' defines it to be. Most Unix systems that define size_t in `sys/types.h', define it to be a signed type. Some code in the library depends on size_t being an unsigned type, and will not work correctly if it is signed.

The GNU C library code which expects size_t to be unsigned is correct. The definition of size_t as a signed type is incorrect. Versions 2.4 and later of GCC always define size_t as an unsigned type, and GCC's `fixincludes' script massages the system's `sys/types.h' so as not to conflict with this.

In the meantime, we work around this problem by telling GCC explicitly to use an unsigned type for size_t when compiling the GNU C library. `configure' will automatically detect what type GCC uses for size_t arrange to override it if necessary.

To build the library, type make lib. This will produce a lot of output, some of which looks like errors from make (but isn't). Look for error messages from make containing `***'. Those indicate that something is really wrong.

To build and run some test programs which exercise some of the library facilities, type make tests. This will produce several files with names like `program.out'.

To format the GNU C Library Reference Manual for printing, type make dvi. To format the Info version of the manual for on line reading with C-h i in Emacs or with the info program, type make info.

To install the library and its header files, and the Info files of the manual, type make install, after setting the installation directories in `configparms'. This will build things if necessary, before installing them.

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