The use of itchconfig for a software package involves the following basic
- The package developer does this:
- execute itchscan to generate configure.scan (optional)
- rename configure.scan to configure.base and edit it as necessary
- execute itchconfig to generate the configure script from
- The user does this:
- execute the configure script to create the Makefile and config.h
- execute make to build the desired executable program(s)
- "make install" to install the built program(s) and any additional files
itchconfig tries to distinguish and separate the following items
- the needs and properties of a package - in configure.base files
- the knowledge about possible portability issues - in the script
- user preferences - in command-line options for configure scripts and in configure.site scripts
In short: configure.base declares what shall be done, the resulting
configure script determines how it is done.
When a package developer executes itchscan, this checks all files in
the current directory and all sub-directories for the following:
- C keywords, types, header file includes, library functions etc. which
aren't available on all computers resp. are known not to work correctly with
all compilers and operating systems
- source code files which might be necessary to build the executable
- files which should be considered for "make install", for example manual
pages, .info files and language-dependent .mo text files
From the results of these checks, itchscan generates the file
configure.scan, which can be used as a starting point for a configure.base
file. Please note that itchconfig can't yet process all commands which are
generated by itchscan; so, before you put a command from configure.scan into
configure.base, you should check (e.g. with the macro index) that the command has already been
When a package developer executes itchconfig, the following
- itchconfig translates configure.base to a temporary, intermediary Perl
script, "configure.pl", which it executes.
- configure.pl creates the final shell script, "configure", which must be
included into the release package.
When a user executes configure, the following happens:
- configure parses its command-line arguments and possibly executes a configure.site script; this information is used to
find out which package features the user wants to enable and where the
generated binaries and other package parts should be installed.
- configure performs all tests on the user's machine which have been
indicated by the original configure.base.
- configure creates a shell script, configure.act, based on the results of
the previous items, and executes that.
- configure.act generates a Makefile and a configuration file config.h; it
also substitutes all variables of the form "@id@" with their actual
values in all relevant .in files as necessary, creating new files without the
- After this, the user can execute "make", "make install" etc. to build an
executable program from the package source files, install it etc.
The file configure.base is some kind of central knowledge database
for a software package. It contains information about all relevant specific
needs and properties of the package - in a single place and encoded in m4 macro
calls. (See the Macro Introduction.) itchconfig reads
this database and creates a configure script file from it. itchconfig makes a
special effort to minimize the size of that script, so that the overall package
size isn't increased more than necessary and package users don't waste time
when running the script. To achieve the design goals, the following ideas are
- All relevant properties of the package must be known to itchconfig,
otherwise it could "mis-optimize" something, producing buggy scripts. One
consequence of this is that all relevant information must be encoded in m4
macro calls, not in shell script code (because itchconfig can't analyze the
latter). itchconfig allows the addition of raw shell script code to the
configure script file for maximum flexibility (see IC_EMIT_SH), but this capability
shouldn't be used too much...
- An intermediary script (configure.pl) is necessary. It checks which
features are actually required for the package and leaves out anything
unnecessary. For example, if a package only needs a Makefile and no config.h,
no code for producing/handling a config.h file has to be added to the final
configure script, so it's simply omitted for this package.
This documentation file is part of version 0.0.4 of itchconfig, a configuration tool
created by Arne Thomaßen. itchconfig is basically
released under certain versions of the GNU General Public License and WITHOUT
ANY WARRANTY. Copyright (C) 2002 Arne Thomaßen.