On Thu, Nov 16, 2000 at 08:12:49PM -0800, Mark Wedel wrote: > At least on my linux box, the defined value for O_NONBLOCK is different than > the defined value for MSG_DONTWAIT. But perhaps an #ifdnef MSG_DONTWAIT/define > MSG_DONTWAIT O_NONBLOCK/#endif is the best way to handle that. No, most systems just don't have any sendto() flag that makes this function call non-blocking even if the socket is blocking. O_NONBLOCK is not to be used in the sendto() flags argument. You should set O_NONBLOCK in the socket flags with fcntl(F_SETFL/F_GETFL). -- Jan