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NAME

LockRecord
Locks a portion of a file (V36)

SYNOPSIS

success = LockRecord(fh,offset,length,mode,timeout)
D0 D1 D2 D3 D4 D5

BOOL LockRecord(BPTR,ULONG,ULONG,ULONG,ULONG)

FUNCTION

This locks a portion of a file for exclusive access. Timeout is how long to wait in ticks (1/50 sec) for the record to be available.

Valid modes are:

Note:
For the IMMED modes, the timeout is always ignored.

Record locks are tied to the FileHandle used to create them. The same FileHandle can get any number of exclusive locks on the same record, for example. These are cooperative locks because they only affect other people calling LockRecord().

INPUTS

fh
File handle for which to lock the record

offset
Record start position

length
Length of record in bytes

mode
Type of lock requester

timeout
Timeout interval in ticks. 0 is legal.

RESULT

success
Success or failure

BUGS

In 2.0 through 2.02 (V36), LockRecord() only worked in the ramdisk. Attempting to lock records on the disk file system causes a crash. This was fixed for V37.

SEE ALSO

LockRecords(), UnLockRecord(), UnLockRecords()