httpd.lock files

[gjansky]

I've written a script that mails me system statuses at various times throughout the day. One of the things I watch for is unlinked, hidden files. I do this by using lsof +L1.
My reports show a couple of instances of the following:

COMMAND PID USER FD TYPE DEVICE SIZE NLINK NODE NAME
httpd 522 root 18w REG 3,7 0 0 163907 /var/run/httpd.lock.522 (deleted)


I'm assuming that these are innoccuous. My questions are:
1. how did these get created?
2. how can I prevent them from showing up? (ie, is there some way of getting rid of these?)

Thanks.

Greg