-# manywarnings.m4 serial 4
-dnl Copyright (C) 2008-2012 Free Software Foundation, Inc.
+# manywarnings.m4 serial 5
+dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# make sure your gcc understands it.
AC_DEFUN([gl_MANYWARN_ALL_GCC],
[
- dnl First, check if -Wno-missing-field-initializers is needed.
- dnl -Wmissing-field-initializers is implied by -W, but that issues
- dnl warnings with GCC version before 4.7, for the common idiom
- dnl of initializing types on the stack to zero, using { 0, }
+ dnl First, check for some issues that only occur when combining multiple
+ dnl gcc warning categories.
AC_REQUIRE([AC_PROG_CC])
if test -n "$GCC"; then
- dnl First, check -W -Werror -Wno-missing-field-initializers is supported
+ dnl Check if -W -Werror -Wno-missing-field-initializers is supported
dnl with the current $CC $CFLAGS $CPPFLAGS.
AC_MSG_CHECKING([whether -Wno-missing-field-initializers is supported])
AC_CACHE_VAL([gl_cv_cc_nomfi_supported], [
])
AC_MSG_RESULT([$gl_cv_cc_nomfi_needed])
fi
+
+ dnl Next, check if -Werror -Wuninitialized is useful with the
+ dnl user's choice of $CFLAGS; some versions of gcc warn that it
+ dnl has no effect if -O is not also used
+ AC_MSG_CHECKING([whether -Wuninitialized is supported])
+ AC_CACHE_VAL([gl_cv_cc_uninitialized_supported], [
+ gl_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS -Werror -Wuninitialized"
+ AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[]], [[]])],
+ [gl_cv_cc_uninitialized_supported=yes],
+ [gl_cv_cc_uninitialized_supported=no])
+ CFLAGS="$gl_save_CFLAGS"])
+ AC_MSG_RESULT([$gl_cv_cc_uninitialized_supported])
+
fi
+ # List all gcc warning categories.
gl_manywarn_set=
for gl_manywarn_item in \
-W \
gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
done
- # Disable the missing-field-initializers warning if needed
+ # Disable specific options as needed.
if test "$gl_cv_cc_nomfi_needed" = yes; then
gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers"
fi
+ if test "$gl_cv_cc_uninitialized_supported" = no; then
+ gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized"
+ fi
+
$1=$gl_manywarn_set
])