PHP Australia Conference 2015

SplFileObject::flock

(PHP 5 >= 5.1.0)

SplFileObject::flockPortable file locking

Description

public bool SplFileObject::flock ( int $operation [, int &$wouldblock ] )

Locks or unlocks the file in the same portable way as flock().

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).
  • LOCK_NB to not block while locking (not supported on Windows).

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!";
}
?>

See Also

  • flock() - Portable advisory file locking

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User Contributed Notes 1 note

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-1
digitalprecision at gmail dot com
3 years ago
For the record, the example given here has an explicit command to truncate the file, however with a 'write mode' of 'w', it will do this for you automatically, so the truncate call is not needed.
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