[adding bug-gnulib] On 05/25/2011 03:29 PM, Eric Blake wrote: >>> building coreutils-8.12 with '--enable-gcc-warnings' fails on my SLES 10.3 >>> server: >>> >>> CC uinttostr.o >>> cc1: warnings being treated as errors >>> In file included from uinttostr.c:3: >>> anytostr.c: In function 'uinttostr': >>> anytostr.c:39: warning: comparison of unsigned expression < 0 is always >>> false >> >> the warning is spurious. But we don't know how >> to shut up gcc. > > You're not the first to hit this, either: > > http://lists.gnu.org/archive/html/bug-gnulib/2010-10/msg00435.html > > Since our party line back then was to "upgrade gcc or quit using -Werror > with old gcc", I'm marking this as a wontfix; but if you can come up > with a patch, we can reopen it.
Jim, Paul,
This patch silences the gcc warning even for gcc too old to honor the
pragma, but I can't help but feel that it might be too gross (it makes
functions like uinttostr larger in size). What do you think?
diff --git i/lib/anytostr.c w/lib/anytostr.c
index e23746a..da57259 100644
--- i/lib/anytostr.c
+++ w/lib/anytostr.c
@@ -17,11 +17,6 @@
/* Written by Paul Eggert */
-/* Tell gcc not to warn about the (i < 0) test, below. */
-#if (__GNUC__ == 4 && 3 <= __GNUC_MINOR__) || 4 < __GNUC__
-# pragma GCC diagnostic ignored "-Wtype-limits"
-#endif
-
#include <config.h>
#include "inttostr.h"
@@ -34,15 +29,17 @@ char * __attribute_warn_unused_result__
anytostr (inttype i, char *buf)
{
char *p = buf + INT_STRLEN_BOUND (inttype);
+ inttype ii = i;
*p = 0;
- if (i < 0)
+ if (i <= 0)
{
do
*--p = '0' - i % 10;
while ((i /= 10) != 0);
- *--p = '-';
+ if (ii)
+ *--p = '-';
}
else
{
The same trick of swapping '< 0' to '<= 0' to foil -Wtype-limits can be
used to reduce (but not eliminate) some of the other warnings generated
by intprops.h. For example, this one's completely safe, and knocks out
a bunch of the warnings on test-intprops.c if you temporarily revert
9d196fad:
diff --git i/lib/intprops.h w/lib/intprops.h
index d722648..c2e6bf8 100644
--- i/lib/intprops.h
+++ w/lib/intprops.h
@@ -54,7 +54,7 @@
/* Return 1 if the integer expression E, after integer promotion, has
a signed type. E should not have side effects. */
-#define _GL_INT_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
+#define _GL_INT_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) <= 0)
/* Minimum and maximum values for integer types and expressions. These
--
Eric Blake ebl...@redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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