MySQL Tutorial/Miscellaneous Functions/IS FREE LOCK

IS_FREE_LOCK(str): Checks whether the lock named str is free to use (that is, not locked).

Returns 1 if the lock is free (no one is using the lock), 0 if the lock is in use, and NULL if an error occurs (such as an incorrect argument).

22. 6. IS_FREE_LOCK 22. 6. 1. IS_FREE_LOCK(str): Checks whether the lock named str is free to use (that is, not locked).