Example of locking and unlocking files with PHP, _PHP tutorial

PHP locks and unlocks files,

Sometimes your php script may need thread safety guarantee, such as when performing file writing operations. This article provides file locking functions and usage examples. The file locking function can also be used to obtain exclusive processing space to prevent synchronization errors in script execution.

Copy code The code is as follows:

/*************************************************************************
*file lock
*@author Zeal Li
*http://www.zeali.net/
*
*************************************************************************/
/*
*lock_thisfile: Obtain exclusive lock
*@param $tmpFileStr The file name used as the shared lock file (you can give it any name)
*@param $locktype lock type, the default is false (non-blocking, that is, once the lock fails, it will directly return false). If set to true, it will wait for the lock to be successful before returning
*@return If the lock is successful, return the lock instance (this parameter is required when using the unlock_thisfile method), if the lock fails, return false.
*/

function lock_thisfile($tmpFileStr,$locktype=false){

if($locktype == false)

$locktype = LOCK_EX|LOCK_NB;

$can_write = 0;

$lockfp = @fopen($tmpFileStr.".lock","w");

if($lockfp){

$can_write = @flock($lockfp,$locktype);

}

if($can_write){

return $lockfp;

}

else{

if($lockfp){

               @fclose($lockfp);

                 @unlink($tmpFileStr.".lock");

}

return false;

}

}

/**
*unlock_thisfile: Unlock the previously obtained lock instance
*@param $fp The return value of the lock_thisfile method
*@param $tmpFileStr The file name used as the shared lock file (you can give it any name)
*/
function unlock_thisfile($fp,$tmpFileStr){

@flock($fp,LOCK_UN);

@fclose($fp);

@fclose($fp);

@unlink($tmpFileStr.".lock");

}
?>

Copy code The code is as follows:

//Usage examples
$tmpFileStr = "/tmp/mylock.loc";
// Wait for the operation permission to be obtained. If you want to return immediately, set the second parameter to false.
$lockhandle = lock_thisfile($tmpFileStr,true);
if($lockhandle){
// All transactions that require exclusive processing are performed here.
// ... ...
// Transaction completed.
​ unlock_thisfile($lockhandle,$tmpFileStr);
}
?>

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