Re: C11 atomics

[Bruno Haible]

Torvald Riegel wrote:
> IMHO, gnulib synchronization primitives should simply move towards the
> semantics chosen by C++11 and more recent (if you dislike C++ for some
> reason, just use the C++ semantics applied to C11; C is lacking behind
> in terms of preciseness of the specification).
> 
> Of course you can build your own, but that requires expertise and time.

gnulib is there to help adoption of POSIX and newer C standards. For
instance, with gnulib you could use <stdint.h> since 2004, long before
all platforms had it. (Even recently, in glibc 2.24, there was an issue
with SIZE_MAX in <stdint.h> on s390 architecture.) gnulib does its best
to shield its users from such portability problems.

Regarding atomics, I agree it's good to have a standard in this area.
But I fear gnulib can do less than it does for <stdint.h>, because the
implementation is highly CPU and OS dependent. Just take a look at
GCC's libatomic...

gnulib code will, when all recently enough systems support it, be able
to use <stdatomic.h>. But this will take years. Maybe 5 years, more
likely something like 10 years.

Bruno