## LOCK

PURPOSE:
To obtain exclusive access to a file.

    STATEMENT SYNTAX:
    {stno} LOCK (unit {,ERR=stno})

    EXAMPLE:
    0230 LOCK(9,ERR=0240)
    0500 LOCK(U+1)

NOTES: The LOCK command provides a means of preventing other users from accessing a specific file. The LOCK command prevents the OPENing of the file by any other user(the other user gets an error 0). Similarly, a file cannot be LOCKed if it is already in use by another user. In this case, an error 0 will occur on execution of the LOCK command.
The exclusive access to the file is released by the UNLOCK command or by closing the file.
See EXTRACT for locking only a single record.
LOCK is a no-op in FreeSM32 !!
Under LINUX your can not LOCK against yourself only other PID's!!