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Although the GNU standards allow the use of ANSI C, this can have the effect of limiting portability of a package to some older compilers (notably SunOS).
Automake allows you to work around this problem on such machines by “de-ANSI-fying” each source file before the actual compilation takes place.
If the Makefile.am variable AUTOMAKE_OPTIONS
(Changing Automake’s Behavior) contains the option ansi2knr
then code to handle de-ANSI-fication is inserted into the generated
Makefile.in.
This causes each C source file in the directory to be treated as ANSI C.
If an ANSI C compiler is available, it is used. If no ANSI C compiler
is available, the ansi2knr program is used to convert the source
files into K&R C, which is then compiled.
The ansi2knr program is simple-minded. It assumes the source
code will be formatted in a particular way; see the ansi2knr man
page for details.
De-ANSI-fication support requires the source files ansi2knr.c and
ansi2knr.1 to be in the same package as the ANSI C source; these
files are distributed with Automake. Also, the package
configure.in must call the macro AM_C_PROTOTYPES.
Automake also handles finding the ansi2knr support files in some
other directory in the current package. This is done by prepending the
relative path to the appropriate directory to the ansi2knr
option. For instance, suppose the package has ANSI C code in the
src and lib subdirs. The files ansi2knr.c and
ansi2knr.1 appear in lib. Then this could appear in
src/Makefile.am:
AUTOMAKE_OPTIONS = ../lib/ansi2knr
If no directory prefix is given, the files are assumed to be in the current directory.
Next: Automatic dependency tracking, Previous: C++ and other languages, Up: Building Programs and Libraries [Contents][Index]