concurrent_unordered_set::size Method
Returns the number of elements in this concurrent container. This method is concurrency safe.
size_type size() const;
Return Value
The number of items in the container.
Remarks
In the presence of concurrent inserts, the number of elements in the concurrent container may change immediately after calling this function, before the return value is even read.
Requirements
Header: internal_concurrent_hash.h
Namespace: concurrency