SplFileObject::flock()
(PHP 5 >= 5.1.0, PHP 7)
Portable file locking
说明
public SplFileObject::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"); $file->flock(LOCK_UN); // release the lock } else { echo "Couldn't get the lock!"; } ?>
更新日志
版本 | 说明 |
---|---|
5.5.22, 5.6.6 | Added support for the$wouldblockparameter 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
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.