From: Josh Huber <huber@...>
Date: 2000-10-20T21:59:50+09:00
Subject: [ruby-talk:5709] build warning...


--oTHb8nViIGeoXxdp
Content-Type: multipart/mixed; boundary="QTprm0S8XgL7H0Dt"
Content-Disposition: inline


--QTprm0S8XgL7H0Dt
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

My primary platform is powerpc, and I'm really used to seeing:
'Comparison always true/false due to limited range in data type'

spit out by gcc due to the fact that on x86 (and other LE archs) char
defaults to signed char, but on the ppc (and ARM, don't know about
sparc) char =3D=3D unsigned char.

for example:
void main(void) {
        char t;
        int i =3D -1;
        t =3D i;
        printf("val: %d\n", (int)t);
}

prints
val =3D 255
on powerpc, but
val =3D -1
on intel.

normally this can cause major problems, and I saw this while building
ruby.  the warning was actually in the parser...

line 3520 of parse.y contains is_identchar(tok()[0]).  tok()
(tokenbuf) is a char *, and is_identchar does this:
((int)(c))!=3D-1 ...

of course, this will always be true on ppc systems.

now, I don't think there's really a problem, because I _think_
tokenbuf characters are never set to a negative value. (could be
wrong, but I didn't see any cases).

in any case, a fix is attached.  this would fix future (obscure) bugs,
and at least get rid of that warning.  (that warning is flagged on the
debian buildd for powerpc because it is usually an indication that
something is broken).

Thanks,

--=20
Josh
| huber@mclx.com |
1024D/6B21489A 61F0 6138 BE7B FEBF A223  E9D1 BFE1 2065 6B21 489A

--QTprm0S8XgL7H0Dt
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment; filename=ruby-signed-char
Content-Transfer-Encoding: quoted-printable

--- ruby-1.6.1/build-tree/ruby-1.6.1/parse.y	Fri Oct 20 08:57:16 2000
+++ parse.y	Fri Oct 20 08:56:31 2000
@@ -1822,7 +1822,7 @@
=20
 #define is_identchar(c) (((int)(c))!=3D-1&&(ISALNUM(c) || (c) =3D=3D '_' |=
| ismbchar(c)))
=20
-static char *tokenbuf =3D NULL;
+static signed char *tokenbuf =3D NULL;
 static int   tokidx, toksiz =3D 0;
=20
 static NODE *str_extend();
@@ -2080,7 +2080,7 @@
=20
 static void
 tokadd(c)
-    char c;
+    signed char c;
 {
     tokenbuf[tokidx++] =3D c;
     if (tokidx >=3D toksiz) {

--QTprm0S8XgL7H0Dt--

--oTHb8nViIGeoXxdp
Content-Type: application/pgp-signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.3 (GNU/Linux)
Comment: For info see http://www.gnupg.org

iEYEARECAAYFAjnwQbUACgkQv+EgZWshSJrZUwCgmwny7VUa8+c+wPiwDdii8WOZ
zDsAnA5Ts3dw8GvOZAMoukk15i6D2ww/
=+iGM
-----END PGP SIGNATURE-----

--oTHb8nViIGeoXxdp--