Re: [PATCH] jit: Ensure ssize_t is defined.

[Iain Sandoe <iain@sandoe.co.uk>]

> On 11 Jun 2024, at 09:06, Richard Biener <rguenther@suse.de> wrote:
> 
> On Tue, 11 Jun 2024, Richard Biener wrote:
> 
>> On Tue, 11 Jun 2024, Iain Sandoe wrote:
>> 
>>> 
>>> 
>>>> On 11 Jun 2024, at 08:44, Jakub Jelinek <jakub@redhat.com> wrote:
>>>> 
>>>> On Tue, Jun 11, 2024 at 09:27:37AM +0200, Richard Biener wrote:
>>>>> On Tue, 11 Jun 2024, FX Coudert wrote:
>>>>> 
>>>>>> Hi
>>>>>> 
>>>>>> I can’t seem to get a review of this one-line patch. Could a global reviewer help?
>>>>> 
>>>>> While stdio.h can be relied on to exist I do not think you can assume
>>>>> the same for sys/types.h without "configury", but libgccjit.h is an
>>>>> installed API.  I would assume including stdlib.h gets you ssize_t as 
>>>>> well?
>>>> 
>>>> If stdlib.h includes sys/types.h like often on Linux, yes, but not
>>>> necessarily.  ssize_t is a POSIX type and it might be solely in sys/types.h.
>>> 
>>> .. and that is the case for at least some affected Darwin versions (stdlib.h
>>> does not include sys/types.h).
>>> 
>>>> Perhaps libgccjit.h could use
>>>> #ifdef __has_include
>>>> #if __has_include (<sys/types.h>)
>>>> #include <sys/types.h>
>>>> #endif
>>>> #endif
>>> 
>>> That seems like a good solution to me.
>>> (my original patch was conditional on __APPLE__ but it seems that the
>>> issue could exist on other platforms too).
>> 
>> Don't you also need to add
>> 
>> approrpiate #define _POSIX_C_SOURCE or #define _XOPE_SOURCE befor the
>> include in case somebody builds with -std=c99?

well, afaict, all the code is c++ and we are building with a std >= 11, so that
presumes c99 support.  I can confirm that, at least on Darwin, we do not need
to define either _POSIX_C_SOURCE, or _XOPEN_SOURCE to get the 
correct behaviour.

> Oh, and the manpage says that <stdio.h> also defines ssize_t which
> is a bit odd since we already include that ...

that seems to be the case for darwin >= 11 but not before.

Iain

> 
> Richard.
> 
>> Richard.
>> 
>>> Iain
>>> 
>>>> instead of just #include <sys/types.h>.
>>>> When compiled by gcc, one can use hacks like
>>>> #define unsigned signed
>>>> typedef __SIZE_TYPE__ gcc_jit_ssize_t;
>>>> #undef unsigned
>>>> but that might not work with other compilers and is perhaps
>>>> just too ugly.
>>>> 
>>>>> In fact the C11 standard doesn't even mention ssize_t so the
>>>>> API should probably avoid using it and instead use size_t for
>>>>> 
>>>>> /* Given type "T", get its size.
>>>>>  This API entrypoint was added in LIBGCCJIT_ABI_20; you can test for its
>>>>>  presence using
>>>>>    #ifdef LIBGCCJIT_HAVE_SIZED_INTEGERS  */
>>>>> extern ssize_t
>>>>> gcc_jit_type_get_size (gcc_jit_type *type);
>>>> 
>>>> 	Jakub
>>> 
>>> 
>> 
>> 
> 
> -- 
> Richard Biener <rguenther@suse.de>
> SUSE Software Solutions Germany GmbH,
> Frankenstrasse 146, 90461 Nuernberg, Germany;
> GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)