unique_lock::try_lock Method
Attempts to obtain ownership of the associated mutex without blocking.
bool try_lock() _NOEXCEPT;
Return Value
true if the method successfully obtains ownership of the mutex; otherwise, false.
Remarks
If the stored mutex pointer is null, the method throws a system_error that has an error code of operation_not_permitted.
If the calling thread already owns the mutex, the method throws a system_error that has an error code of resource_deadlock_would_occur.
Requirements
Header: mutex
Namespace: std