Try to find a compiler option that requires strict prototypes.
The sanity check is done by looking at sys/signal.h which has a set
of macro-definitions SIG_DFL and SIG_IGN that are cast to the local
signal-handler type. If that signal-handler type is not fully
qualified then the system headers are not seen as strictly
prototype clean.
For the GNU CC compiler it will be -fstrict-prototypes
-Wstrict-prototypes The result is added to the shellvar being
CFLAGS by default.
DEFAULTS:
- $1 shell-variable-to-add-to : CFLAGS
- $2 add-value-if-not-found : nothing
- $3 action-if-found : add value to shellvariable
- $4 action-if-not-found : nothing
AC_DEFUN([AX_CFLAGS_STRICT_PROTOTYPES],[dnl
AS_VAR_PUSHDEF([FLAGS],[CFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cflags_strict_prototypes])dnl
AC_CACHE_CHECK([m4_ifval($1,$1,FLAGS) for strict prototypes],
VAR,[VAR="no, unknown"
AC_LANG_SAVE
AC_LANG_C
ac_save_[]FLAGS="$[]FLAGS"
for ac_arg dnl
in "-pedantic % -fstrict-prototypes -Wstrict-prototypes" dnl GCC
"-pedantic % -Wstrict-prototypes" dnl try to warn atleast
"-pedantic % -Wmissing-prototypes" dnl or another warning
"-pedantic % -Werror-implicit-function-declaration" dnl
"-pedantic % -Wimplicit-function-declaration" dnl
#
do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
AC_TRY_COMPILE([],[return 0;],
[VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
done
case ".$VAR" in
.|.no|.no,*) ;;
*) # sanity check with signal() from sys/signal.h
cp config.log config.tmp
AC_TRY_COMPILE([#include <signal.h>],[
if (signal (SIGINT, SIG_IGN) == SIG_DFL) return 1;
if (signal (SIGINT, SIG_IGN) != SIG_DFL) return 2;],
dnl the original did use test -n `$CC testprogram.c`
[if test `diff config.log config.tmp | grep -i warning | wc -l` != 0
then if test `diff config.log config.tmp | grep -i warning | wc -l` != 1
then VAR="no, suppressed, signal.h," ; fi ; fi],
[VAR="no, suppressed, signal.h"])
rm config.tmp
;;
esac
FLAGS="$ac_save_[]FLAGS"
AC_LANG_RESTORE
])
case ".$VAR" in
.ok|.ok,*) m4_ifvaln($3,$3) ;;
.|.no|.no,*) m4_ifvaln($4,$4,[m4_ifval($2,[
AC_RUN_LOG([: m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $2"])
m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $2"])]) ;;
*) m4_ifvaln($3,$3,[
if echo " $[]m4_ifval($1,$1,FLAGS) " | grep " $VAR " 2>&1 >/dev/null
then AC_RUN_LOG([: m4_ifval($1,$1,FLAGS) does contain $VAR])
else AC_RUN_LOG([: m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $VAR"])
m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $VAR"
fi ]) ;;
esac
AS_VAR_POPDEF([VAR])dnl
AS_VAR_POPDEF([FLAGS])dnl
])
dnl the only difference - the LANG selection... and the default FLAGS
AC_DEFUN([AX_CXXFLAGS_STRICT_PROTOTYPES],[dnl
AS_VAR_PUSHDEF([FLAGS],[CXXFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cxxflags_strict_prototypes])dnl
AC_CACHE_CHECK([m4_ifval($1,$1,FLAGS) for strict prototypes],
VAR,[VAR="no, unknown"
AC_LANG_SAVE
AC_LANG_CPLUSPLUS
ac_save_[]FLAGS="$[]FLAGS"
for ac_arg dnl
in "-pedantic -Werror % -fstrict-prototypes -Wstrict-prototypes" dnl GCC
"-pedantic -Werror % -Wstrict-prototypes" dnl try to warn atleast
"-pedantic -Werror % -Wmissing-prototypes" dnl try to warn atleast
"-pedantic -Werror % -Werror-implicit-function-declaration" dnl
"-pedantic -Werror % -Wimplicit-function-declaration" dnl
"-pedantic % -Wstrict-prototypes %% no, unsupported in C++" dnl oops
#
do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
AC_TRY_COMPILE([],[return 0;],
[VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
done
case ".$VAR" in
.|.no|.no,*) ;;
*) # sanity check with signal() from sys/signal.h
cp config.log config.tmp
AC_TRY_COMPILE([#include <signal.h>],[
if (signal (SIGINT, SIG_IGN) == SIG_DFL) return 1;
if (signal (SIGINT, SIG_IGN) != SIG_DFL) return 2;],
dnl the original did use test -n `$CC testprogram.c`
[if test `diff config.log config.tmp | grep -i warning | wc -l` != 0
then if test `diff config.log config.tmp | grep -i warning | wc -l` != 1
then VAR="no, suppressed, signal.h," ; fi ; fi],
[VAR="no, suppressed, signal.h"])
rm config.tmp
;;
esac
FLAGS="$ac_save_[]FLAGS"
AC_LANG_RESTORE
])
case ".$VAR" in
.ok|.ok,*) m4_ifvaln($3,$3) ;;
.|.no|.no,*) m4_ifvaln($4,$4,[m4_ifval($2,[
AC_RUN_LOG([: m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $2"])
m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $2"])]) ;;
*) m4_ifvaln($3,$3,[
if echo " $[]m4_ifval($1,$1,FLAGS) " | grep " $VAR " 2>&1 >/dev/null
then AC_RUN_LOG([: m4_ifval($1,$1,FLAGS) does contain $VAR])
else AC_RUN_LOG([: m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $VAR"])
m4_ifval($1,$1,FLAGS)="$m4_ifval($1,$1,FLAGS) $VAR"
fi ]) ;;
esac
AS_VAR_POPDEF([VAR])dnl
AS_VAR_POPDEF([FLAGS])dnl
])