PHP check if file locked with flock()?

Question

Will fopen() fail if a file exists, but is currently locked with LOCK_EX?

Or do I have to open it, and then try and set a lock, in

Answer 1

flock() doesn't actually prevent you from reading/writing to a file, it only allows you to "communicate" the ideas of locking to other scripts. You can detect if there is a lock on a file using the snippet you posted.