HP 3000 Manuals HP 3000 Manuals
UNLOCK Statement (Executable) The UNLOCK statement unlocks a record that was locked by a READ on an ISAM file. If an ISAM file is shared by more than one process, you should unlock the records after each READ if they are not being updated. If the file is not shared, UNLOCK has no effect.----------------------------------------------------------------------------------------------- | | | | | Item | Description/Default | Restrictions | | | | | ----------------------------------------------------------------------------------------------- | | | | | unit | Integer expression specifying | Must be zero or positive. | | | unit number of a connected file. | | | | | | ----------------------------------------------------------------------------------------------- | | | | | variable_name | Error code return. | Must be an integer type. | | array_element | | | | scalar_record_field_name | | | | | | ----------------------------------------------------------------------------------------------- | | | | | label | Statement label. | Must be an executable statement | | | | in the same program unit. | | | | | ----------------------------------------------------------------------------------------------- Semantics If the prefix UNIT= is omitted, unit must be the first item in the list. If the ERR specifier is present and an error occurs during execution of the UNLOCK statement, control transfers to the specified statement rather than aborting the program. If the IOSTAT specifier is present and an error occurs, the error code is returned in the IOSTAT variable and the program is not aborted. Refer to Appendix A for the IOSTAT error codes. If the file is positioned at its beginning, a UNLOCK statement has no effect upon the file. Examples Notes -------------------------------------------------------------------------------------- OPEN(10,file='EMP_FILE', This example generates a report. +ACCESS='KEYED',STATUS='OLD',SHARED) The READ statement locks the 111 READ (10,ERR=111,END=222) EMPLOY_REC record when it reads it. The UNLOCK (10,ERR=112) UNLOCK statement unlocks the PRINT 11,EMPLOYEE_REC.SSN, record to allow other users to + EMPLOYEE_REC.FIRST_NAME access it. If the record is + EMPLOYEE_REC.LAST_NAME, locked by another user, the ERR + EMPLOYEE_REC.SALARY, specifier causes the READ + EMPLOYEE_REC.REVIEW_DATE statement to be reexecuted until GOTO 111 the record is available. 112 PRINT *,'Can not unlock: ssn', EMPLOYEE_REC.SSN GOTO 111 222 PRINT *,'Employee salary review report printed' STOP
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