[vlc-devel] [PATCH] compat: work-around busted FreeBSD qsort_r()

[Marvin Scholz]

On 29 Nov 2018, at 17:17, Rémi Denis-Courmont wrote:

> Hi,
>
> Thanks for the review. As I cannot test it (or cannot be bothered to 
> install a FreeBSD VM), I have no plans to update the patch myself 
> though.

Ok, understandable. I will try to come up with a solution.

Currently the only good approach I can see is to give the compat 
function
a different name, like vlc_qsort_r and if the system provides a 
non-broken
qsort_r then just `#define vlc_qsort_r qsort_r` instead of compiling the
compat one.

Any objections and/or better ideas how to do this?

>
> Le 29 novembre 2018 14:33:44 GMT+02:00, Marvin Scholz 
> <epirat07 at gmail.com> a écrit :
>> On 20 Nov 2018, at 17:16, Rémi Denis-Courmont wrote:
>>
>>> This is untested.
>>> ---
>>>  configure.ac         | 15 +++++++++++++++
>>>  include/vlc_fixups.h |  4 ++++
>>>  2 files changed, 19 insertions(+)
>>>
>>> diff --git a/configure.ac b/configure.ac
>>> index 1f33f5dc88..21fcb45203 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -742,6 +742,21 @@ AC_CHECK_LIB([m], [sincos], [
>>>    AC_LIBOBJ([sincos])
>>>  ])
>>>
>>> +AC_MSG_CHECKING([broken qsort_r prototype])
>>> +AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <stdlib.h>
>>> +
>>> +_Static_assert(_Generic((qsort_r),
>>> +    void (*)(void *, size_t, size_t, void *,
>>> +             int (*)(void *, const void *, const void *)) : 1,
>>> default: 0),
>>> +    "Bad prototype not matched");
>>> +])], [
>>> +  AC_MSG_RESULT([broken])
>>> +  AC_DEFINE([HAVE_BROKEN_QSORT_R], 1, [Defined to 1 if the 
>>> qsort_r()
>>
>>> prototype contradicts the upcoming POSIX standard.])
>>> +  AC_LIBOBJ([qsort_r])
>>> +], [
>>> +  AC_MSG_RESULT([no])
>>> +])
>>> +
>>>  AC_MSG_CHECKING([_Thread_local support])
>>>  AC_COMPILE_IFELSE([AC_LANG_SOURCE([_Thread_local int foo = 0;
>>>                     int main() {}])], [
>>> diff --git a/include/vlc_fixups.h b/include/vlc_fixups.h
>>> index 0263286efc..45fec0f6d4 100644
>>> --- a/include/vlc_fixups.h
>>> +++ b/include/vlc_fixups.h
>>> @@ -224,6 +224,10 @@ long long atoll (const char *);
>>>  lldiv_t lldiv (long long, long long);
>>>  #endif
>>>
>>> +#ifdef HAVE_BROKEN_QSORT_R
>>> +# define qsort_r posix_qsort_r
>>> +#endif
>>> +
>>>  #ifndef HAVE_QSORT_R
>>>  void (qsort_r)(void *, size_t, size_t,
>>>                 int (*)(const void *, const void *, void *), void 
>>> *);
>>> -- 
>>> 2.19.1
>>
>> Thanks for the patch, this actually affects Darwin too and probably
>> every other BSD variant.
>>
>> With the patch applied configure properly detects the qsort_r as 
>> having
>>
>> the
>> wrong prototype but the compat replacement collides with the already
>> existing
>> qsort_r declaration:
>>
>>   CC       qsort_r.lo
>> ../../extras/package/macosx/../../../compat/qsort_r.c:41:6: error:
>> conflicting types for 'posix_qsort_r'
>> void qsort_r(void *base, size_t nmemb, size_t size,
>>      ^
>> ../../extras/package/macosx/../../../include/vlc_fixups.h:228:18: 
>> note:
>>
>> expanded from macro 'qsort_r'
>> # define qsort_r posix_qsort_r
>>                  ^
>> /[...]/usr/include/stdlib.h:330:7: note: previous declaration is here
>> void     qsort_r(void *__base, size_t __nel, size_t __width, void *,
>>          ^
>> ../../extras/package/macosx/../../../include/vlc_fixups.h:228:18: 
>> note:
>>
>> expanded from macro 'qsort_r'
>> # define qsort_r posix_qsort_r
>>                  ^
>> 1 error generated.
>> make[3]: *** [qsort_r.lo] Error 1
>>
>>>
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