wincache_lock

(PECL wincache >= 1.1.0)

wincache_lock — Acquires an exclusive lock on a given key

说明

bool wincache_lock ( string $key [, bool $isglobal = false ] )

Obtains an exclusive lock on a given key. The execution of the current script will be blocked until the lock can be obtained. Once the lock is obtained, the other scripts that try to request the lock by using the same key will be blocked, until the current script releases the lock by using wincache_unlock().

Warning

Using of the wincache_lock() and wincache_unlock() can cause deadlocks when executing PHP scripts in a multi-process environment like FastCGI. Do not use these functions unless you are absolutely sure you need to use them. For the majority of the operations on the user cache it is not necessary to use these functions.

参数

key: Name of the key in the cache to get the lock on.
isglobal: Controls whether the scope of the lock is system-wide or local. Local locks are scoped to the application pool in IIS FastCGI case or to all php processes that have the same parent process identifier.

返回值

成功时返回 TRUE，或者在失败时返回 FALSE。

范例

Example #1 Using wincache_lock()


<?php
$fp = fopen("/tmp/lock.txt", "r+");
if (wincache_lock("lock_txt_lock")) { // do an exclusive lock
    ftruncate($fp, 0); // truncate file
    fwrite($fp, "Write something here\n");
    wincache_unlock("lock_txt_lock"); // release the lock
} else {
    echo "Couldn't get the lock!";
}
fclose($fp);
?>

参见

wincache_unlock() - Releases an exclusive lock on a given key
wincache_ucache_set() - Adds a variable in user cache and overwrites a variable if it already exists in the cache
wincache_ucache_get() - Gets a variable stored in the user cache
wincache_ucache_delete() - Deletes variables from the user cache
wincache_ucache_clear() - Deletes entire content of the user cache
wincache_ucache_exists() - Checks if a variable exists in the user cache
wincache_ucache_meminfo() - Retrieves information about user cache memory usage
wincache_ucache_info() - Retrieves information about data stored in the user cache
wincache_scache_info() - Retrieves information about files cached in the session cache

User Contributed Notes

donraman at microsoft dot com 24-Apr-2010 03:11


User should be aware that character '\' is not allowed as part of lock name. The reason why backslash is not allowed is because we are using CreateMutex call as described at http://msdn.microsoft.com/en-us/library/ms682411(VS.85).aspx. As per this article third parameter cannot have '\' character which is the lock name.



This means below code will not work.



<?php



   $ret_val = wincache_lock("C:\WINDOWS\Temp/cache");

   echo $ret_val . '<br>';

   $ret_val = wincache_unlock("C:\WINDOWS\Temp/cache");

   echo $ret_val . '<br>';



?>