folly::call_once

Synopses

Declared in <folly/synchronization/CallOnce.h>

Grants the free call_once access to the flag internals.

template<
    typename OnceFlag,
    typename F,
    typename... Args>
void
call_once(
    OnceFlag&,
    F&&,
    Args&&...);

Drop-in replacement for std::call_once.

template<
    typename OnceFlag,
    typename F,
    typename... Args>
void
call_once(
    OnceFlag& flag,
    F&& f,
    Args&&... args);

Name	Description
flag	The once-flag guarding the call.
f	The callable to invoke at most once.
args	The arguments to forward to the callable.