>>>>> "UG" == Uri Guttman <[EMAIL PROTECTED]> writes: UG> it it not about how hard it is to implement, but how hard it is to hide UG> implementation details from the language specs. in this case it is very UG> hard. signals are messy. I'm sorry, please expound on this. I can't see where you have to get into the details. Isn't it enough to state that signals will only be delivered at (pick one or more) statement boundary expression boundary checkpoint boundary thread switch context switch io event calls to the yield operator There are even more possiblities. None of which requires any mention of how the internals are implemented. As far as I can see there is nothing in the %SIG semantics that makes it inherently unsafe. If there is please tell me why this isn't a callback scheme which you feel is safe. <chaim> -- Chaim Frenkel Nonlinear Knowledge, Inc. [EMAIL PROTECTED] +1-718-236-0183