The RECORDLOCKED function can be called to ascertain the status of a record lock.
filevar is a file variable from a previously executed OPEN
RECORDLOCKED returns an integer value to indicated the record lock status of the specified record id.
If the return value is negative, then the SYSTEM(43) and STATUS function calls can be used to determine the port number of the program that holds the lock. If -1 is returned, more than 1 port could hold the lock and so the port number returned will be the first port number found.]