Since when does Perl have get_lock/unlock functions?

As for whether or not, and if yes, how, you should use flock depends on what you are exactly doing. Normally you need to flock files if there's a change that if one process is modifying a file, another process is accessing the file (be it for reading or writing). The syntactical details about file locking can be found in perldoc -f flock and in man perlipc.

Abigail