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
SyncMutex::unlock
(PECL sync >= 1.0.0)
SyncMutex::unlock — Unlocks the mutex
설명
public bool SyncMutex::unlock
([ bool
$all
] )Decreases the internal counter of a SyncMutex object. When the internal counter reaches zero, the actual lock on the object is released.
인수
-
all -
Specifies whether or not to set the internal counter to zero and therefore release the lock.
반환값
A boolean of TRUE if the unlock operation was successful, FALSE otherwise.
예제
Example #1 SyncMutex::unlock() example
<?php
$mutex = new SyncMutex("UniqueName");
$mutex->lock();
/* ... */
$mutex->unlock();
?>
참고
- SyncMutex::lock() - Waits for an exclusive lock
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User Contributed Notes 1 note
npelov at croler dot net ¶
4 years ago
