Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.UUCP
Newsgroups: comp.unix.questions
Subject: Re: question about signal
Message-ID: <6487@brl-smoke.ARPA>
Date: Mon, 28-Sep-87 15:32:32 EDT
Article-I.D.: brl-smok.6487
Posted: Mon Sep 28 15:32:32 1987
Date-Received: Tue, 29-Sep-87 04:49:00 EDT
References: <720001@hpclmar.HP.COM>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 16

In article <720001@hpclmar.HP.COM> mar@hpclmar.HP.COM (Michelle Ruscetta) writes:
>  Should the return from a signal handling routine specified by a call
>  to signal() go to the instruction which caused the signal, or to the 
>  instruction immediately following that which caused the signal?

If it's an asynchronous trap, it should complete the interrupted
instruction sequence.  If it's a synchronous trap (e.g. SIGFPE),
there is no "right" answer.  Presumably the synchronous exception
occurred because some machine operation had invalid operands;
unless you can be sure that the signal handler has fixed the
operands (which is almost never the case, due to code optimization
etc.), retrying the faulting instruction would just cause another
trap.

Portable, robust programs should not just return from a SIGFPE
handler.