AX_CFLAGS_GCC_OPTION(-fvomit-frame) would show a message as like
"checking CFLAGS for gcc -fvomit-frame ... yes" and adds the
optionflag to CFLAGS if it is understood. You can override the
shellvar-default of CFLAGS of course. The order of arguments stems
from the explicit macros like AX_CFLAGS_WARN_ALL.
The cousin AX_CXXFLAGS_GCC_OPTION would check for an option to add
to CXXFLAGS - and it uses the autoconf setup for C++ instead of C
(since it is possible to use different compilers for C and C++).
The macro is a lot simpler than any special AX_CFLAGS_* macro (or
ac_cxx_rtti.m4 macro) but allows to check for arbitrary options.
However, if you use this macro in a few places, it would be great
if you would make up a new function-macro and submit it to the
ac-archive.
- $1 option-to-check-for : required ("-option" as non-value)
- $2 shell-variable-to-add-to : CFLAGS (or CXXFLAGS in the other case)
- $3 action-if-found : add value to shellvariable
- $4 action-if-not-found : nothing
note: in earlier versions, $1-$2 were swapped. We try to detect the
situation and accept a $2=~/-/ as being the old
option-to-check-for.
also: there are other variants that emerged from the original macro
variant which did just test an option to be possibly added.
However, some compilers accept an option silently, or possibly for
just another option that was not intended. Therefore, we have to do
a generic test for a compiler family. For gcc we check "-pedantic"
being accepted which is also understood by compilers who just want
to be compatible with gcc even when not being made from gcc
sources.
see also:
AX_CFLAGS_SUN_OPTION AX_CFLAGS_HPUX_OPTION
AX_CFLAGS_AIX_OPTION AX_CFLAGS_IRIX_OPTION
AC_DEFUN([AX_CFLAGS_GCC_OPTION_OLD], [dnl
AS_VAR_PUSHDEF([FLAGS],[CFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cflags_gcc_option_$2])dnl
AC_CACHE_CHECK([m4_ifval($1,$1,FLAGS) for gcc m4_ifval($2,$2,-option)],
VAR,[VAR="no, unknown"
AC_LANG_SAVE
AC_LANG_C
ac_save_[]FLAGS="$[]FLAGS"
for ac_arg dnl
in "-pedantic % m4_ifval($2,$2,-option)" dnl GCC
#
do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
AC_TRY_COMPILE([],[return 0;],
[VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
done
FLAGS="$ac_save_[]FLAGS"
AC_LANG_RESTORE
])
case ".$VAR" in
.ok|.ok,*) m4_ifvaln($3,$3) ;;
.|.no|.no,*) m4_ifvaln($4,$4) ;;
*) 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_GCC_OPTION_OLD], [dnl
AS_VAR_PUSHDEF([FLAGS],[CXXFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cxxflags_gcc_option_$2])dnl
AC_CACHE_CHECK([m4_ifval($1,$1,FLAGS) for gcc m4_ifval($2,$2,-option)],
VAR,[VAR="no, unknown"
AC_LANG_SAVE
AC_LANG_CXX
ac_save_[]FLAGS="$[]FLAGS"
for ac_arg dnl
in "-pedantic % m4_ifval($2,$2,-option)" dnl GCC
#
do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
AC_TRY_COMPILE([],[return 0;],
[VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
done
FLAGS="$ac_save_[]FLAGS"
AC_LANG_RESTORE
])
case ".$VAR" in
.ok|.ok,*) m4_ifvaln($3,$3) ;;
.|.no|.no,*) m4_ifvaln($4,$4) ;;
*) 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 -------------------------------------------------------------------------
AC_DEFUN([AX_CFLAGS_GCC_OPTION_NEW], [dnl
AS_VAR_PUSHDEF([FLAGS],[CFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cflags_gcc_option_$1])dnl
AC_CACHE_CHECK([m4_ifval($2,$2,FLAGS) for gcc m4_ifval($1,$1,-option)],
VAR,[VAR="no, unknown"
AC_LANG_SAVE
AC_LANG_C
ac_save_[]FLAGS="$[]FLAGS"
for ac_arg dnl
in "-pedantic % m4_ifval($1,$1,-option)" dnl GCC
#
do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
AC_TRY_COMPILE([],[return 0;],
[VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
done
FLAGS="$ac_save_[]FLAGS"
AC_LANG_RESTORE
])
case ".$VAR" in
.ok|.ok,*) m4_ifvaln($3,$3) ;;
.|.no|.no,*) m4_ifvaln($4,$4) ;;
*) m4_ifvaln($3,$3,[
if echo " $[]m4_ifval($2,$2,FLAGS) " | grep " $VAR " 2>&1 >/dev/null
then AC_RUN_LOG([: m4_ifval($2,$2,FLAGS) does contain $VAR])
else AC_RUN_LOG([: m4_ifval($2,$2,FLAGS)="$m4_ifval($2,$2,FLAGS) $VAR"])
m4_ifval($2,$2,FLAGS)="$m4_ifval($2,$2,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_GCC_OPTION_NEW], [dnl
AS_VAR_PUSHDEF([FLAGS],[CXXFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cxxflags_gcc_option_$1])dnl
AC_CACHE_CHECK([m4_ifval($2,$2,FLAGS) for gcc m4_ifval($1,$1,-option)],
VAR,[VAR="no, unknown"
AC_LANG_SAVE
AC_LANG_CXX
ac_save_[]FLAGS="$[]FLAGS"
for ac_arg dnl
in "-pedantic % m4_ifval($1,$1,-option)" dnl GCC
#
do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
AC_TRY_COMPILE([],[return 0;],
[VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
done
FLAGS="$ac_save_[]FLAGS"
AC_LANG_RESTORE
])
case ".$VAR" in
.ok|.ok,*) m4_ifvaln($3,$3) ;;
.|.no|.no,*) m4_ifvaln($4,$4) ;;
*) m4_ifvaln($3,$3,[
if echo " $[]m4_ifval($2,$2,FLAGS) " | grep " $VAR " 2>&1 >/dev/null
then AC_RUN_LOG([: m4_ifval($2,$2,FLAGS) does contain $VAR])
else AC_RUN_LOG([: m4_ifval($2,$2,FLAGS)="$m4_ifval($2,$2,FLAGS) $VAR"])
m4_ifval($2,$2,FLAGS)="$m4_ifval($2,$2,FLAGS) $VAR"
fi ]) ;;
esac
AS_VAR_POPDEF([VAR])dnl
AS_VAR_POPDEF([FLAGS])dnl
])
AC_DEFUN([AX_CFLAGS_GCC_OPTION],[ifelse(m4_bregexp([$2],[-]),-1,
[AX_CFLAGS_GCC_OPTION_NEW($@)],[AX_CFLAGS_GCC_OPTION_OLD($@)])])
AC_DEFUN([AX_CXXFLAGS_GCC_OPTION],[ifelse(m4_bregexp([$2],[-]),-1,
[AX_CXXFLAGS_GCC_OPTION_NEW($@)],[AX_CXXFLAGS_GCC_OPTION_OLD($@)])])