Re: A strange gcc behavior, and an argument against -Wno-unused

[Pedro Alves <pedro@codesourcery.com>]

On Saturday 10 October 2009 19:10:36, Eli Zaretskii wrpte:

> What version of GCC introduced this switch?

If you're worried about breaking the build with older
gcc's, note that gdb/configure.ac filters out -W options
that gcc doesn't recognize.

if test "x${build_warnings}" != x -a "x$GCC" = xyes
then
    AC_MSG_CHECKING(compiler warning flags)
    # Separate out the -Werror flag as some files just cannot be
    # compiled with it enabled.
    for w in ${build_warnings}; do
	case $w in
	-Werr*) WERROR_CFLAGS=-Werror ;;
	*) # Check that GCC accepts it
	    saved_CFLAGS="$CFLAGS"
	    CFLAGS="$CFLAGS $w"
	    AC_TRY_COMPILE([],[],WARN_CFLAGS="${WARN_CFLAGS} $w",)
	    CFLAGS="$saved_CFLAGS"
	esac
    done
    AC_MSG_RESULT(${WARN_CFLAGS} ${WERROR_CFLAGS})
fi

That said, I don't know when the switch was introduced
in gcc.

-- 
Pedro Alves