SplFileObject::flock()

(PHP 5 >= 5.1.0, PHP 7)

Portable file locking

说明

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

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

参数

$operation

$operationis 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.

$wouldblock

Set to TRUE if the lock would block(EWOULDBLOCK errno condition).

返回值

成功时返回TRUE，或者在失败时返回FALSE。

范例

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!";
}
?>

更新日志

参见

• flock()轻便的咨询文件锁定

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.