SyncMutex::unlock

(PECL sync >= 1.0.0)

SyncMutex::unlock — Unlocks the mutex

説明

public SyncMutex::unlock(bool $all = false): bool

Decreases the internal counter of a SyncMutex object. When the internal counter reaches zero, the actual lock on the object is released.

パラメータ

all: Specifies whether or not to set the internal counter to zero and therefore release the lock.

戻り値

成功した場合に true を、失敗した場合に false を返します。

例

例1 SyncMutex::unlock() example

<?php
$mutex = new SyncMutex("UniqueName");

$mutex->lock();

/* ... */

$mutex->unlock();
?>

参考

SyncMutex::lock() - Waits for an exclusive lock

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User Contributed Notes 1 note

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npelov at croler dot net ¶

4 years ago

If the php process dies unexpectedly (on linux) the lock will remain with no option to remove it. unlock() will not work if the lock is being held by other process. SyncMutex uses shared mem. in that case you can delete the shared memory object in /dev/shm. To list the objects:

ls /dev/shm/Sync_Mutex*

Keep in mind that objects remain there even after unlocking. So if you use lots of random mutex names then the number of these objects will grow and and you might want to cleanup at some point

Example sync.php:
<?php

$s = new SyncMutex("mymutex");

if(!$s->lock()){
  echo "cannot lock\n";
  exit;
}
echo "locked\n";
sleep(10);
$s->unlock();
echo "unlocked\n";
?>

then run:

php -f sync.php

and press ctrl-c. If you run it again it won't lock. So what you can do is:

rm -f /dev/shm/Sync_Mutex-*-mymutex

Then run it again - it'll lock again

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