using flock() on an array of file paths not working

Question

I have a function that locks all files in a certain folder:

function lockFolder_files($folder='',$task=''){

global $file_array;//I need to use this var outside the function too

$file_array=glob($folder . '*_che.php');//this lists all files ending with "_che.php" in the array from folder1.

//now do a foreach on the array and open the file, and lock it:

foreach($file_array as $path){

$lock=fopen($path,"a+")//open with append mode

if($task=="lock"){
flock($lock,LOCK_EX);
}
elseif($task=="unlock"){
flock($lock,LOCK_UN);
}

}//end of foreach

if(count($file_array)==0){echo"no files were found in the folder"; return false;}

}//end of function

So I call this function :

lockFolder_files("blah1/blah/myfolder","lock");

//do what i need to do with the array of files locked ($file_array)

lockFolder_files("blah1/blah/myfolder","unlock");//unlock all the files

Now it seems to find all the files in the folder, assign them to the array, but for some reason, it doesn't seem to lock the files. After testing it (using sleep() and attempting to write to the file with other scripts) the flock() seems to be having no effect on the files what so ever....

Any ideas why this is happening?

Thanks

Answer 1

Two things:

• file locking with *nix is not mandatory, only if all software uses flock() access is synchronized.
• The problem is caused by PHPs garbage collection. After the function returns, all files are closed and therefore all locks are released automatically. You have to keep them open if you want the locks to stay.