[FFmpeg-devel] [PATCH] fix compilation in cygwin

[Vitor Sessak]

M?ns Rullg?rd wrote:
> Vitor Sessak <vitor1001 at gmail.com> writes:
> 
>> M?ns Rullg?rd wrote:
>>> Vitor Sessak <vitor1001 at gmail.com> writes:
>>>
>>>> M?ns Rullg?rd wrote:
>>>>> Michael Kostylev <michael.kostylev at gmail.com> writes:
>>>>>
>>>>>> On Sun Jan 10 21:55:50 2010
>>>>>> Vitor Sessak wrote:
>>>>>>
>>>>>>>>> +#if !HAVE_EXP2F
>>>>>>>>> +static av_always_inline av_const float exp2f(float x)
>>>>>>>>> +{
>>>>>>>>> +    return exp(x) * 0.693147180559945;
>>>>>>>>> +}
>>>>>>>>> +#endif /* HAVE_EXP2F */
>>>>>>>> Same again.  exp2() should be preferred.
>>>>>>> Let's hope that at least exp2() is supported...
>>>>>> exp2() is missing in NetBSD and DragonFly.
>>>>> We have a replacement for it, so it's OK.
>>>> We have a replacement for log2(), but not for exp2().
>>>>
>>>> I'm slightly favorable of adding a replacement for exp2() (as
>>>> attached) as we do for log2(), since we can get some speed gain in
>>>> platforms where exp2() is supported and we'll eventually need exp2()
>>>> sooner or later.
>>>>
>>>> [...]
>>> Well, this caused things to break in new and interesting ways:
>>> libavutil/internal.h:275: error: static declaration of 'exp2f'
>>> follows non-static declaration
>>> libavutil/internal.h:296: error: static declaration of 'log2f' follows non-static declaration
>>> uClibc apparently has declarations for those functions, but no actual
>>> implementations.  This is truly the week of idiots.
>> BTW, wouldn't compilation fail if log2f() is a macro?
> 
> No.  The functions are required to be available as actual functions,
> even if a macro is also defined.

What about if we define them as macros? Should work on any case.

-Vitor
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