NWLockLogicalRecordSet
Locks all logical records logged in the log table
#include <nwfile.h>
or
#include <nwcalls.h>
N_EXTERN_LIBRARY( NWCCODE )NWLockLogicalRecordSet (
nuint8 lockFlags,
nuint16 timeOut);
uses calwin32
Function NWLockLogicalRecordSet
(lockFlags : nuint8;
timeOut : nuint16
) : NWCCODE;
These are common return values; see Return Values (NDK: Connection, Message, and NCP Extensions) for more information.
Applications define logical record names. A logical record name represents a group of files, physical records, or data structures. NWLogLogicalRecord and NWLockLogicalRecordSet affect one or more logical record names, not the actual files, physical records, or data structures associated with each logical record name. Any uncooperative application can ignore a lock on the logical record name and directly lock physical files or records. Therefore, applications using logical record locks must not simultaneously use other locking techniques.
To avoid deadlock, request the resources needed to lock by making an entry in the File Log Table at the NetWare server. Once the log table is complete, the application attempts to lock those records. The locking works only if all records in the table are available. If some of the logged resources cannot be locked, the lock fails and none of the resources are locked.
A logical record is simply a name (a string) registered with the NetWare server. The name (as with a semaphore) can then be locked or unlocked by applications and can be used as an inter-application locking mechanism.
NOTE:Locking or unlocking a logical record does not physically lock or unlock those resources associated with the logical record; only the applications using the record know about such an association.
lockFlags is interpreted as follows:
0x00 Lock record with a shareable lock 0x01 Lock record with an exclusive loc
timeOut is specified in units of 1/18 second (0 = no wait).