[libvirt] build failure on 32-bit

[Daniel P. Berrange]

On Tue, Jul 12, 2016 at 11:48:11AM -0600, Eric Blake wrote:
> I hit an interesting failure on my 32-bit F24 machine:
> 
> In file included from ../../src/util/virconf.c:32:0:
> ../../src/util/virconf.c: In function 'virConfGetValueSSizeT':
> ../../src/util/virconf.c:1269:26: error: format '%zd' expects argument
> of type 'signed size_t', but argument 9 has type 'long int'
> [-Werror=format=]
>                         _("%s: value for '%s' parameter must be in range
> %zd:%zd"),
> 
> In context, it is because we are using SSIZE_MAX as the argument paired
> to %zd.
> 
> Technically, the standards documents do NOT require ssize_t to have any
> relation to size_t, and thus there is NO portable way to pass ssize_t
> values to printf() without a cast; but in practice, most systems are
> sane enough that 'ssize_t' is the same type as 'signed size_t', as
> requested by gcc.  This includes 32-bit glibc (where size_t is unsigned
> int, and ssize_t is int).
> 
> But it turns out it is a glibc bug:
> https://sourceware.org/bugzilla/show_bug.cgi?id=13575 - SSIZE_MAX must
> have type ssize_t, and glibc is at fault for defining it as a 'long'
> value even when ssize_t is an 'int'.
> 
> Once gnulib works around it, I'll update libvirt's gnulib submodule to
> fix the libvirt build on 32-bit Linux again.

Should we just add a cast temporarily ?


Regards,
Daniel
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