AC_PROG_CC_NO_WRITEABLE_STRINGS(substvar [,hard])
, 

2005年01月25日

Guido U. Draheim <guidod@gmx.de>

GPLWithACException
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guidod's Obsoleted (obsoleted)

• obsoleted Use AX_CFLAGS_NO_WRITABLE_STRINGS.

Try to find a compiler option that warns when a stringliteral is used in a place that could potentially modify the address. This should warn on giving an stringliteral to a function that asks of a non-const-modified char-pointer.

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.

Currently this macro knows about GCC. hopefully will evolve to use: Solaris C compiler, Digital Unix C compiler, C for AIX Compiler, HP-UX C compiler, and IRIX C compiler.

AC_DEFUN([AC_PROG_CC_NO_WRITEABLE_STRINGS], [
 pushdef([CV],ac_cv_prog_cc_no_writeable_strings)dnl
 hard=2ドル
 if test -z "$hard"; then
 msg="C to warn about writing to stringliterals"
 else
 msg="C to prohibit any write to stringliterals"
 fi
 AC_CACHE_CHECK($msg, CV, [
 cat > conftest.c <<EOF
#include <string.h>
int main (void)
{
 char test[[16]];
 if (strcpy (test, "test")) return 0;
 return 1;
}
EOF
 dnl GCC
 if test "$GCC" = "yes";
 then
 if test -z "$hard"; then
 CV="-Wwrite-strings"
 else
 CV="-fno-writable-strings -Wwrite-strings"
 fi
 if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then
 CV="suppressed: string.h"
 fi
 dnl Solaris C compiler
 elif $CC -flags 2>&1 | grep "Xc.*strict ANSI C" > /dev/null 2>&1 &&
 $CC -c -xstrconst conftest.c > /dev/null 2>&1 &&
 test -f conftest.o
 then
 # strings go into readonly segment
 CV="-xstrconst"
 rm conftest.o
 if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then
 CV="suppressed: string.h"
 fi
 dnl HP-UX C compiler
 elif $CC > /dev/null 2>&1 &&
 $CC -c +ESlit conftest.c > /dev/null 2>&1 &&
 test -f conftest.o
 then
 # strings go into readonly segment
 CV="+ESlit"
 rm conftest.o
 if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then
 CV="suppressed: string.h"
 fi
 dnl Digital Unix C compiler
 elif ! $CC > /dev/null 2>&1 &&
 $CC -c -readonly_strings conftest.c > /dev/null 2>&1 &&
 test -f conftest.o
 then
 # strings go into readonly segment
 CV="-readonly_strings"
 rm conftest.o
 if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then
 CV="suppressed: string.h"
 fi
 dnl C for AIX Compiler
 dnl IRIX C compiler
 # -use_readonly_const is the default for IRIX C,
 # puts them into .rodata, but they are copied later.
 # need to be "-G0 -rdatashared" for strictmode but
 # I am not sure what effect that has really.
 fi
 rm -f conftest.*
 ])
 if test -z "[$]1ドル" ; then
 if test -n "$CV" ; then
 case "$CV" in
 suppressed*) 1ドル="" ;; # known but suppressed
 *) 1ドル="$CV" ;;
 esac
 fi
 fi
 AC_SUBST(1ドル)
 popdef([CV])dnl
])