http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59337
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The standard doesn't allow it, and given the parsing complexities of the atomics creating extensions there is IMHO undesirable, especially when it will unlikely work with other compilers. Because the standard explicitly lists the operators that can be used, I'd just do s/must be /must be binary / in the message.
