Re: [PATCH 64bit] ssize_t

[Eric Blake <eblake at redhat dot com>]

On 02/20/2013 09:56 AM, Corinna Vinschen wrote:
> On Feb 20 09:36, Eric Blake wrote:
>> On 02/20/2013 09:30 AM, Schwarz, Konrad wrote:
>>
>>>>>> GCC requires exact symmetry of types between ssize_t and size_t.
>>>>>> I.e. checking for sizes of types is not sufficient for [s]size_t.
>>
>>>
>>> Pardon me, but would an approach similar to the following work?
>>>
>>> # include <limits.h>
>>>
>>> typedef int
>>> # if USHRT_MAX == __SIZE_MAX__
>>> 	short
>>> # elif UINT_MAX == __SIZE_MAX__
>>
>> No, because when size_t and long are 4 bytes, UINT_MAX == LONG_MAX, but
>> that's a case where we want ssize_t to be long, not int.
> 
> Do we really?  I thought that int is preferred if int == long.

I guess it boils down to: can we guarantee that if 'int', 'long', and
'size_t' are all the same size, then 'size_t' was based on 'int' instead
of 'long'?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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