[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [libvirt] [PATCH] build: trivial fix error: implicit declaration of function 'malloc'

On Thu, 22 Nov 2012 06:53:12 -0700
Eric Blake <eblake redhat com> wrote:

> On 11/22/2012 06:46 AM, Natanael Copa wrote:
> >> If your headers are defining this in terms of malloc(), then IMHO,
> >> the sched.h should be including stdlib.h on our behalf. IOW, I
> >> think this is a bug in the c library headers
> > 
> > You are right. uclibc does this:
> > 
> > #if 0 /* in uClibc we use macros */
> > extern cpu_set_t *__sched_cpualloc (size_t __count) __THROW __wur;
> > extern void __sched_cpufree (cpu_set_t *__set) __THROW;
> > #else
> > # define __sched_cpualloc(cnt) ((cpu_set_t *)malloc(__CPU_ALLOC_SIZE(cnt)))
> Ouch.
> > # define __sched_cpufree(__set) free(__set)
> > #endif
> > 
> > And since this is only a warning, I don't think its worth the effort.
> And that's where you're wrong.  Using malloc() without a prototype means
> you are attempting to call 'int malloc(int)' instead of 'void
> *malloc(size_t)'; and if sizeof(size_t)>sizeof(int) (as on most 64-bit
> platforms), you have silently miscompiled.  The warning exists for a
> reason, and we only have K&R C to blame that this is just a warning
> rather than a hard error by default (at least C++ did it right by
> mandating it as a hard error).

You are of course right. I'll forward it to uclibc devs right away.
Ugly thing.


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]