For non-futex targets the __platform_wait_t type is currently uint64_t,
but that requires a lock in libatomic for some 32-bit targets. We don't
really need a 64-bit type, so use unsigned long if that is lock-free,
and int otherwise. This should mean it's lock-free on a wider set of
targets.
libstdc++-v3/ChangeLog:
* include/bits/atomic_wait.h (__detail::__platform_wait_t):
Define as unsigned long if always lock-free, and unsigned int
otherwise.
// and __platform_notify() if there is a more efficient primitive supported
// by the platform (e.g. __ulock_wait()/__ulock_wake()) which is better than
// a mutex/condvar based wait.
- using __platform_wait_t = uint64_t;
+# if ATOMIC_LONG_LOCK_FREE == 2
+ using __platform_wait_t = unsigned long;
+# else
+ using __platform_wait_t = unsigned int;
+# endif
inline constexpr size_t __platform_wait_alignment
= __alignof__(__platform_wait_t);
#endif