Another feature of the choice to make semaphores/FIFOs/shared memory segments different from file descriptors is that select(3) presumably won't work with them. How does one check the condition "is data ready on my queue or on my UDP port?" Thanks, -- John Riedl {ucbvax,decvax,hplabs}!purdue!riedl -or- riedl at mordred.cs.purdue.edu