Functions listed by SuSv3 but not (yet) included in uClibc

Sergio M. Ammirata, Ph.D. sergio at
Tue Jan 12 16:38:09 UTC 2010


Compiling x264 has the same problem ...I patched x264 and ffmpeg by
replacing log2f(i) with logf(i)/logf(2) since logf is supported by uclibc.


On 1/12/10 10:32 AM, "A. Craig West" <acraigwest at> wrote:

> I recently ran into a problem building ffmpeg on a uclibc system,
> where ffmpeg appears to depend on the log2f function. A bit of
> investigation led me to a section of code in libm/float_wrappers.c,
> with #undef L_log2f, and the comment:
>  /* For the time being, do _NOT_ implement these functions
>  * that are defined by SuSv3 */
> What is missing is any explanation of WHY these functions are left
> unimplemented. There is the secondary issue of why ffmpeg requires
> this function, but that isn't really pertinent to this list...
> -A. Craig West
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