AX_CFLAGS_NO_WRITABLE_STRINGS [(shellvar [,default, [A/NA]])]
, 

2006年10月13日

Guido U. Draheim <guidod@gmx.de>

GPLWithACException
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation. As a special exception, the respective Autoconf Macro's copyright owner gives unlimited permission to copy, distribute and modify the configure scripts that are the output of Autoconf when processing the Macro. You need not follow the terms of the GNU General Public License when using or distributing such scripts

cryp.to ac-archive's C Support (released)

Try to find a compiler option that makes all stringliteral readonly.

The sanity check is done by looking at string.h which has a set of strcpy definitions that should be defined with const-modifiers to not emit a warning in all so many places.

For the GNU CC compiler it will be -fno-writable-strings -Wwrite-strings The result is added to the shellvar being CFLAGS by default.

DEFAULTS:

• - 1ドル shell-variable-to-add-to : CFLAGS

• - 2ドル add-value-if-not-found : nothing

• - 3ドル action-if-found : add value to shellvariable

• - 4ドル action-if-not-found : nothing

AC_DEFUN([AX_CFLAGS_NO_WRITABLE_STRINGS],[dnl
AS_VAR_PUSHDEF([FLAGS],[CFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cflags_no_writable_strings])dnl
AC_CACHE_CHECK([m4_ifval([1ドル],[1ドル],FLAGS) making strings readonly],
VAR,[VAR="no, unknown"
 AC_LANG_SAVE
 AC_LANG_C
 ac_save_[]FLAGS="$[]FLAGS"
# IRIX C compiler:
# -use_readonly_const is the default for IRIX C,
# puts them into .rodata, but they are copied later.
# need to be "-G0 -rdatashared" for strictmode but
# I am not sure what effect that has really. - guidod
for ac_arg dnl
in "-Wall % -fno-writable-strings -Wwrite-strings" dnl GCC
 "-v -Xc % -xstrconst" dnl Solaris C - strings go into readonly segment
 "+w1 -Aa % +ESlit" dnl HP-UX C - strings go into readonly segment
 "-w0 -std1 % -readonly_strings" dnl Digital Unix - again readonly segment
 "-fullwarn -use_readonly_const %% ok, its the default" dnl IRIX C
 #
do FLAGS="$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 - testing strcpy() from string.h
 cp config.log config.tmp
 AC_TRY_COMPILE([#include <string.h>],[
 char test[16];
 if (strcpy (test, "test")) return 1;],
 dnl the original did use test -n `$CC testprogram.c`
 [if test `diff config.log config.tmp | grep -i warning | wc -l` != 0
 then VAR="no, suppressed, string.h," ; fi],
 [VAR="no, suppressed, string.h"])
 rm config.tmp
 ;;
esac
 FLAGS="$ac_save_[]FLAGS"
 AC_LANG_RESTORE
])
case ".$VAR" in
 .ok|.ok,*) m4_ifvaln(3,ドル3ドル) ;;
 .|.no|.no,*) m4_ifvaln(4,ドル4,ドル[m4_ifval(2,ドル[
 AC_RUN_LOG([: m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) 2ドル"])
 m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) 2ドル"])]) ;;
 *) m4_ifvaln(3,ドル3,ドル[
 if echo " $[]m4_ifval(1,ドル1,ドルFLAGS) " | grep " $VAR " 2>&1 >/dev/null
 then AC_RUN_LOG([: m4_ifval(1,ドル1,ドルFLAGS) does contain $VAR])
 else AC_RUN_LOG([: m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) $VAR"])
 m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) $VAR"
 fi ]) ;;
esac
AS_VAR_POPDEF([VAR])dnl
AS_VAR_POPDEF([FLAGS])dnl
])
dnl the only difference - the LANG selection... and the default FLAGS
AC_DEFUN([AX_CXXFLAGS_NO_WRITABLE_STRINGS],[dnl
AS_VAR_PUSHDEF([FLAGS],[CXXFLAGS])dnl
AS_VAR_PUSHDEF([VAR],[ac_cv_cxxflags_no_writable_strings])dnl
AC_CACHE_CHECK([m4_ifval(1,ドル1,ドルFLAGS) making strings readonly],
VAR,[VAR="no, unknown"
 AC_LANG_SAVE
 AC_LANG_CXX
 ac_save_[]FLAGS="$[]FLAGS"
# IRIX C compiler:
# -use_readonly_const is the default for IRIX C,
# puts them into .rodata, but they are copied later.
# need to be "-G0 -rdatashared" for strictmode but
# I am not sure what effect that has really. - guidod
for ac_arg dnl
in "-Wall % -fno-writable-strings -Wwrite-strings" dnl GCC
 "-v -Xc % -xstrconst" dnl Solaris C - strings go into readonly segment
 "+w1 -Aa % +ESlit" dnl HP-UX C - strings go into readonly segment
 "-w0 -std1 % -readonly_strings" dnl Digital Unix - again readonly segment
 "-fullwarn -use_readonly_const %% ok, its the default" dnl IRIX C
 #
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 - testing strcpy() from string.h
 cp config.log config.tmp
 AC_TRY_COMPILE([#include <string.h>],[[
 char test[16];
 if (strcpy (test, "test")) return 1;]],
 dnl the original did use test -n `$CC testprogram.c`
 [if test `diff config.log config.tmp | grep -i warning | wc -l` != 0
 then VAR="no, suppressed, string.h," ; fi],
 [VAR="no, suppressed, string.h"])
 rm config.tmp
 ;;
esac
 FLAGS="$ac_save_[]FLAGS"
 AC_LANG_RESTORE
])
case ".$VAR" in
 .ok|.ok,*) m4_ifvaln(3,ドル3ドル) ;;
 .|.no|.no,*) m4_ifvaln(4,ドル4,ドル[m4_ifval(2,ドル[
 AC_RUN_LOG([: m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) $VAR"])
 m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) 2ドル"])]) ;;
 *) m4_ifvaln(3,ドル3,ドル[
 if echo " $[]m4_ifval(1,ドル1,ドルFLAGS) " | grep " $VAR " 2>&1 >/dev/null
 then AC_RUN_LOG([: m4_ifval(1,ドル1,ドルFLAGS) does contain $VAR])
 else AC_RUN_LOG([: m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) $VAR"])
 m4_ifval(1,ドル1,ドルFLAGS)="$m4_ifval(1,ドル1,ドルFLAGS) $VAR"
 fi ]) ;;
esac
AS_VAR_POPDEF([VAR])dnl
AS_VAR_POPDEF([FLAGS])dnl
])