Defined in header <mutex> template< class Lockable1, class Lockable2, class... LockableN>
int try_lock( Lockable1& lock1, Lockable2& lock2, LockableN&... lockn); (since C++11)
Tries to lock each of the given Lockable objects lock1, lock2, ..., lockn by calling try_lock in order beginning with the first.
If a call to try_lock fails, unlock is called for any locked objects and a 0-based index of the object that failed to lock is returned.
If a call to try_lo