Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!brl-adm!brl-smoke!gwyn From: gwyn@brl-smoke.ARPA (Doug Gwyn ) Newsgroups: comp.unix.questions Subject: Re: Suspending processes Message-ID: <5507@brl-smoke.ARPA> Date: Sat, 10-Jan-87 14:24:16 EST Article-I.D.: brl-smok.5507 Posted: Sat Jan 10 14:24:16 1987 Date-Received: Mon, 12-Jan-87 21:54:11 EST References: <836@A60.UUCP> Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB)) Organization: Ballistic Research Lab (BRL), APG, MD. Lines: 20 In article <836@A60.UUCP> lee@A60.UUCP (G. Lee) writes: > Does UNIX provide a standard way to suspend a processes ( stop it >from getting CPU time )? There isn't any universal way of doing this, and on some UNIXes there is no way at all. Around SVR2.1 or so, a "switch" character was added for terminals, usually set to ^Z or ^Y, that operates in conjunctions with the "shl" poor-man's process manager to control processes more or less as you seem to wish. 4.1BSD and later include a fancier "job control" mechanism that does similar things in conjunction with a shell that understands this environment (C-shell, BRL Bourne shell, or Korn shell). The System V scheme is cleaner but doesn't provide any way for a process to notice that the terminal display has been asynchronously messed-up by the "shl" operations, which is sometimes quite a nuisance when your resumed screen-oriented software doesn't have any way to request a screen repaint. The best facility I've seen for this is the /proc mechanism of 8th Edition UNIX. Unfortunately I haven't seen this adopted in any generally-available version of UNX.