Question

I have a file I’m writing to, but I need to lock it first (using flock()), to prevent any other script from writing to it.
So I have:

$file=fopen($file_p);

if (flock($file, LOCK_EX)) {//lock was successful
    fwrite($file,$write_contents);          
}

But I need to check if it’s already locked, to prevent other scripts from writing to it.

How can I do this?

Answer 1

I would check to see if I couldn’t obtain a lock on the file, like this:

if (!flock($file, LOCK_EX)) {
    throw new Exception(sprintf('Unable to obtain lock on file: %s', $file));
}

fwrite($file, $write_contents);