#define P99_ONCE_FLAG_INIT   { { 0 } }

expands to a value that can be used to initialize an object of type p99_once_flag

A characteristic of this implementation is that initialization is equivalent to the default initialization by 0, meaning in particular that a p99_once_flag that is of static or thread-local storage duration is by default correctly initialized. This property is subsequently used in the fallback implementation of thread local storage.

See also

Definition at line 62 of file p99_threads_posix.h.