@title{Cygnus Configure} @author{K. Richard Pixley, rich@cygnus.com} @author{Cygnus Support}

Copyright (C) 1991, 1992 Cygnus Support

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What Configure Does

configure prepares source directories for building working programs. A program cannot be built until its source has been configured. When configure runs, it does the following things.

Create build directories

(see section Build Directories). When you run configure with the -srcdir= option, it uses the current directory as build directory, creating under it a directory tree that parallels the directory structure under the source directory. (See section Invoking).

Generate makefiles

A makefile template from the source directory, usually called `Makefile.in', is copied to an output file in the build directory. The output file is usually named `Makefile'. configure places definitions for a number of standard makefile macros at the beginning of the output file. If -prefix= or -exec_prefix were specified on the configure command line, corresponding makefile variables are set accordingly. If host, target, or site specific makefile fragments exist, these are inserted into the output file. (See section `Makefiles' in Makefiles.)

Generate `.gdbinit' If the source directory contains a

`.gdbinit' file and the build directory is not the same as the source directory, a `.gdbinit' file is created in the build directory. This `.gdbinit' file contains dir commands and a source command, which will cause the `.gdbinit' file from the source directory to be read by GDB, and will allow GDB to find source files in either the source directory or the build directory. (see section `Command Files' in Command Files.)

Make symbolic links

Most directories have some symbolic links with generic names built pointing to specific files in the source directory. If the system where configure runs cannot support symbolic links, hard links are used instead.

Miscellaneous

If the source directory has special needs, they are handled by shell script fragments stored with the source. Usually there are no special needs, but sometimes they involve changes to the output makefile.

Generate `config.status'

configure creates a shell script named `config.status' in the build directory. This shell script, when run from the build directory, will reconfigure the build directory (but not its subdirectories). This is most often used to have a Makefile update itself automatically if a new source directory is available.

Recursion

If the source directory has subdirectories that should also be configured, configure is called for each.