Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!philabs!seismo!hao!hplabs!sri-unix!JPAYNE@BBNG.ARPA From: JPAYNE@BBNG.ARPA Newsgroups: net.unix-wizards Subject: sh and sigtstp problem. Message-ID: <3684@sri-arpa.UUCP> Date: Mon, 1-Aug-83 09:27:00 EDT Article-I.D.: sri-arpa.3684 Posted: Mon Aug 1 09:27:00 1983 Date-Received: Thu, 4-Aug-83 00:00:41 EDT Lines: 18 I'm confused. I tried Pausing emacs under /bin/sh and emacs simply returned immediately and repainted the screen. Does this means that the kernel didn't send the signal to the shell? Hey! Wait a minute. The kernel remembers whether or not the new signal mechanism has been used in any way (there is actual a flags somewhere in the u structure I think). It needs to know so it can do the "right" thing with interrupting certain system calls (read/write/wait). Perhaps the kernel refuses to send signals greater than 16, when the new mechanism hasn't been used, so that old programs don't break. SO lets see ... when a program that uses sigset etc. (which sets the flags in the u structure) decides to kill its process group, the kernel says "Okay fine. Lets SIGTSTP the processes in the current process group (which includes the sh)", and then both processes are sleeping. Sound plausible? or am I still confused?