tilly++

Also remember that a close loses the lock.

I'd like to add to that... you lose the lock if you close any filehandle that has the locked file open. Here's some code to make this clearer:

open A, "<foo";
flock A, LOCK_SH;
open B, "<foo";
close B;
# lock on foo is now lost
[download]

This took me forever to track down when my DBM files started getting corrupted a while back...