WTSupported in traditional Synergy on Windows
WNSupported in Synergy .NET on Windows
USupported on UNIX
VSupported on OpenVMS
UNLOCK channel[, RFA:match_rfa]
The channel on which the file is open. (n)
(optional) Unlocks the record with the specified RFA. See RFA for a complete description.
Using the UNLOCK statement on an ISAM file unlocks either the specified RFA or the automatic lock (if RFA is not specified). Usually RFA:match_rfa specifies a manual lock, but an automatic lock will also be unlocked if present. UNLOCK RFA on a non-ISAM file ignores the specified RFA and simply unlocks the automatic lock.
On Windows and UNIX, manual locks must be released individually using RFA, or they will be released all together when the file is closed.
On OpenVMS, if the VMS_UNLOCK_SINGLE environment variable is set (and system option #35 is not set), the UNLOCK statement (without RFA specified) on an indexed or relative file will unlock only the last record.
If system option #35 is set, the UNLOCK statement removes all locks on the specified channel, regardless of whether or not VMS_UNLOCK_SINGLE is set. If no lock conditions exist on the specified channel, UNLOCK is ignored.
The following subroutine unlocks either automatic or manual locks depending on whether the RFA is passed.
subroutine rel_locks a_chn ,n a_rfa ,a proc if (^passed(a_rfa)) then unlock a_chn, RFA:a_rfa else unlock a_chn xreturn endsubroutine
The following example reads and locks a relative record, and then prompts the user to add a new record, change the locked record, delete the locked record, or exit the routine. If the user selects exit or presses the EOF character, the record is explicitly unlocked.
subroutine proc_rec a_chn ,d ;Channel of file open in update mode a_data ,a ;Data record to read a_recnum ,d ;Record number to read .define TTCHN ,1 record ans ,a1 proc read(a_chn, a_data, a_recnum) ;Record locked repeat begin display(TTCHN, "Add/Change/Delete/Exit: ") reads(TTCHN, ans, exit) case ans of begincase "A": xcall add "C": xcall change "D": xcall delete "E": exitloop endcase end exit, unlock a_chn xreturn endsubroutine