std::experimental::latch::count_down(3)

NAME
std::experimental::latch::count_down - std::experimental::latch::count_down

Synopsis
   void count_down( ptrdiff_t n = 1 ); (1) (concurrency TS)
   Atomically decrements the internal counter by n without blocking the caller.
   If n is greater than the value of the internal counter or is negative, the behavior
   is undefined.
   This operation synchronizes with all calls that block on this latch and all is_ready
   calls on this latch that returns true.

Parameters
   n - the value by which the internal counter is decreased

Return value
   (none)

Exceptions
   Throws nothing.