[yocto] libm implementation issue

[Richard Purdie]

On Tue, 2014-12-30 at 20:09 +1030, peterengcomau001 at adam.com.au wrote:
> 
> I have some software that uses specific mathematical functions. When I
> attempt to compile them with the Yocto cross-compile tools, the
> functions are not recognised. E.g. 'pow' in <math>
> According to website https://wiki.yoctoproject.org/wiki/Minimal_Image,
> not all eglibc features are installed as standard, and that I should
> alter my local.conf file. I have added the following:
> 
> DISTRO_FEATURES_LIBC  += " libc-libm "
> DISTRO_FEATURES_append = " ${DISTRO_FEATURES_LIBC} "

By default the libc we build is fully featured. The only time we cut
down the libc by default is when you use DISTRO = "poky-tiny". Are you
using poky-tiny?

If you're not, the most likely issue you didn't see pow and friends
would be a missing linkage against libm (-lm on the commandline for
gcc/ld).

Cheers,

Richard