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SplFileObject::flock

(PHP 5 >= 5.1.0, PHP 7)

SplFileObject::flockPortable file locking

说明

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

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

参数

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.

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

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!";
}
?>

更新日志

版本 说明
5.5.22, 5.6.6 Added support for the wouldblock parameter on Windows.
5.3.2 The automatic unlocking when the file's resource handle is closed was removed. Unlocking now always has to be done manually.

参见

  • flock() - 轻便的咨询文件锁定

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User Contributed Notes 1 note

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2
digitalprecision at gmail dot com
6 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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