Re: [pups] screen 3.9.9 vs. 2.11BSD write() to fifo and/or select() on socket

Hi - :) Adding FIFOs to the kernel would make an interesting project though - perhaps when I become inspired/motivated I'll give it a try. Overlays will help if the code comes out to more than 64KB. Alas, overlays will _not_ help the dataspace requirements. The last time I looked at 'screen' I saw things like "char buf[32768];' sprinkled thru the code. So you might be in for some serious hacking to trim back the sizes of arrays/buffers/etc. It probably would also be a good idea to 'string'ify the program (there are tools to assist doing this - take a look at how sendmail and lint are built). The gospel according to /usr/src/lib/libc/gen/alarm.c says: /* * Backwards compatible alarm. */ #include <sys/time.h> #include <unistd.h> unsigned int alarm(secs) unsigned int secs; { struct itimerval it, oitv; register struct itimerval *itp = &it; timerclear(&itp->it_interval); itp->it_value.tv_sec = secs; itp->it_value.tv_usec = 0; if (setitimer(ITIMER_REAL, itp, &oitv) < 0) return (-1); if (oitv.it_value.tv_usec) oitv.it_value.tv_sec++; return (oitv.it_value.tv_sec); } <g> What I think you're seeing is the race condition that fork() has - there is no guarantee which process (parent or child) runs first. The test program does the fork() and the child runs to completion before the parent enters the select(). At that point the parent will wait until the alarm goes off. One thing you might try is create two separate programs. One would create the socket and wait for the other program to connect and send a string. If that works it shows that the UNIX domainsockets are working as expected and that the fork() race is indeed the problem. IF the client/server tests fail then there is something wrong in the UNIX domain socket handling that needs to be addressed. Good Luck! Cheers, Steven Schultz