long use_count() const noexcept;
Returns the number of
shared_ptr instances that share ownership of the managed object, or 0 if the managed object has already been deleted, i.e. *this is empty.
 Return value
The number of
shared_ptr instances sharing the ownership of the managed object at the instant of the call.
expired() may be faster than
use_count(). This function is inherently racy, if the managed object is shared among threads that might be creating and destroying copies of the
shared_ptr: then, the result is reliable only if it matches the number of copies uniquely owned by the calling thread, or zero; any other value may become stale before it can be used.
|This section is incomplete|
Reason: no example
 See also
| checks whether the referenced object was already deleted |
(public member function)