documentation for __atomic_add?

[Ian Lance Taylor]

Joseph Garvin <joseph.h.garvin@gmail.com> writes:

> The release notes for 4.2 [1] mention some atomic builtins I haven't
> seen documented anywhere, __atomic_add, and __exchange_and_add. I
> assume these are distinct from the __sync builtins. Are they
> documented somewhere? If not what other undocumented builtins are
> there?

__atomic_add and __exchange_and_add are not builtins.  They are
functions provided by the libstdc++ runtime library.  The are documented
at http://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_concurrency.html .

Ian