SplFileObject::flock
Portable file locking
Description
public bool SplFileObject::flock(int $operation, int &$wouldBlock = null)
Parameters
-
operation
-
operation is one of the following:
-
LOCK_SH to acquire a shared lock (reader).
-
LOCK_EX to acquire an exclusive lock (writer).
-
LOCK_UN to release a lock (shared or exclusive).
It is also possible to add LOCK_NB as a bitmask to one
of the above operations, if flock should not
block during the locking attempt.
-
wouldBlock
-
Set to true if the lock would block (EWOULDBLOCK errno condition).
Return Values
Returns true on success or false on failure.
Examples
Example #1 SplFileObject::flock example
<?php
$file = new SplFileObject("/tmp/lock.txt", "w");
if ($file->flock(LOCK_EX)) { // do an exclusive lock
$file->ftruncate(0); // truncate file
$file->fwrite("Write something here\n");
$file->flock(LOCK_UN); // release the lock
} else {
echo "Couldn't get the lock!";
}
?>