[FFmpeg-devel] [PATCH 00/15] replace pow(10, x) by exp10(x) across FFmpeg

[Ronald S. Bultje]

Hi,

On Wed, Dec 23, 2015 at 7:49 PM, Ganesh Ajjanagadde <gajjanag at mit.edu>
wrote:

> What I meant was the following (I casually labelled it as ifdef, I
> meant some preprocessor stuff):
> #if !HAVE_EXP10 || !(defined(_GNU_SOURCE))
> ...
> #endif
>
> I have reproduced your issues via a minimal configure line, and the
> above idea fixes those. Do you see any issues? Of course, there is the
> theoretical one of a libc (more precisely libm) having exp10 without
> GNU_SOURCE, but in that case it should just use the fallback.


I don't like this as much. In all other instances of any other function
whatsoever, we just check if the function exists. We should do the same
thing here. If implemented correctly in configure, #if !HAVE_EXP10 should
always work. If we can fail to compile when compiling some video filter, we
can fail alike when testing for the feature in configure.

Ronald