Taken from the user notes about set_time_limit()

"malhavoc at stomped.com
23-Feb-2001 05:48 
I've noticed that using this function doesn't seem to block things that make calls to services and wait for a response. Setting set_time_limit(2) and then making a call to gethostbyaddr(ip.that.does.not.resolve) just sits there until it times out. 

It would be -really- nice if there was a perl-esque type function like alarm() that lets you set timeouts for specific sections of code, rather than entire scripts. I'd have great use for a feature that would enable me to run non crucial pieces of code for a few seconds, and then give up and move on if it takes too long."

This feature would be very nice.
Thanks for all your efforts,
   --tom