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(PHP 5 >= 5.1.0)
SplFileObject::flock — Portable file locking
$operation
[, int &$wouldblock
] )Locks or unlocks the file in the same portable way as flock() .
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).
成功时返回 TRUE
, 或者在失败时返回 FALSE
。
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!" ;
}
?>
[#1] digitalprecision at gmail dot com [2010-12-24 14:48:29]
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.