Re: [libvirt] Compiler warnings
At 10/18/2011 01:03 AM, Eric Blake Write:
On 10/17/2011 10:17 AM, Alex Jia wrote:
> Eric,
> It's latest libvirt upstream, current commit id is commit 0a71c79.
>
> # rpm -q glibc
> glibc-2.12-1.42.el6.x86_64
>
> 430 if (strchr(toescape, *cur))
>>> CC libvirt_util_la-buf.lo
>>> util/buf.c: In function 'virBufferEscape':
>>> util/buf.c:430: warning: logical '&&' with non-zero constant
will
>>> always
>>> evaluate as true [-Wlogical-op]
Something's screwy. There's no && in that line, unless strchr() is a
macro based on your particular compilation flags. I'm suspecting that
this is a case of -D_FORTIFY_SOURCE going awry. I don't see how this
could possibly be a libvirt issue; more likely, it is an issue with the
choice of compiler flags you are using, coupled with an issue in the
system headers causing the preprocessor to expand strchr() into
something that tickles a spurious gcc warning.
Yes, strchr() is a macro, I use -E, and get the following:
while (*cur != 0) {
if ((__extension__ (__builtin_constant_p (*cur) && !__builtin_constant_p
(toescape) && (*cur) == '\0' ? (char *) __rawmemchr (toescape, *cur) :
__builtin_strchr (toescape, *cur))))
*out++ = '\\';
*out++ = *cur;
cur++;
}
*out = 0;
Thanks
Wen Congyang