IB Statements/lock
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(New page: '''LOCK statement''' '''Syntax:''' LOCK (lun) [,EXCP=statement-label] '''Discussion:''' The LOCK statement locks a logical unit number. It is a way to prevent a specified file from ...) |
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'''Discussion:''' The LOCK statement locks a logical unit number. It is a way to prevent a specified file from being opened by another user. | '''Discussion:''' The LOCK statement locks a logical unit number. It is a way to prevent a specified file from being opened by another user. |
Revision as of 22:12, 28 May 2009
LOCK statement
Syntax: LOCK (lun) [,EXCP=statement-label | NOEXCP]
Discussion: The LOCK statement locks a logical unit number. It is a way to prevent a specified file from being opened by another user.
The lun parameter is a numeric or symbolic constant that is previously assigned to a file by an OPEN statement -- it represents the logical unit to be locked.
If th LOCK statement is attempted while another user has the particular file open, an exception 7 (FILE UNAVAILABLE -- LOCK/UNLOCK ERROR) will be encountered.
Example: OPEN (1) "FILEB"
LOCK (1)
.
.
UNLOCK (1)
CLOSE (1)