std::experimental::latch:: latch

From cppreference.com
explicit latch ( ptrdiff_t value ) ;
(1) (concurrency TS)
latch ( const latch & ) = delete ;
(2) (concurrency TS)
1) Constructs a latch and initializes its internal counter.
2) Copy constructor is deleted. latch is not copyable.

Parameters

value - the initial value of the internal counter; must be non-negative