Re: [boost] ARM platform: undefined reference to __sync_fetch_and_add_4

From: Peter Dimov (pdimov_at_[hidden])
Date: 2008-04-03 13:42:21

Rob Desbois wrote:
> I cannot link against Boost libraries 1.35.0 built with CodeSourcery's
> ARM/GNU toolchain, although the build is successful.
...

> undefined reference to `__sync_fetch_and_add_4'
> collect2: ld returned 1 exit status
>
> With assistance on the boost-build list I've ascertained that the
> problem is that GCC doesn't support __sync_fetch_and_add and the other
> atomic built-ins on ARM.
> An additional case for this may need to be added to
> boost/detail/sp_counted_base.hpp
>
> I don't know enough to patch boost for this, short-term or otherwise;
> can anyone offer any advice?

Two workarounds are available: define BOOST_SP_DISABLE_THREADS to disable 
MT-safety for the reference count, or define BOOST_SP_USE_PTHREADS to use a 
pthread_mutex.