From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <ac4210fe8560e9c8511064fefd908a10@terzarima.net>
To: fernanbolando@mailc.net, 9fans@9fans.net
From: Charles Forsyth <forsyth@terzarima.net>
Date: Fri,  4 Jul 2008 10:59:30 +0100
In-Reply-To: <1d5d51400807040117i242cae83y6d65e8972748ea47@mail.gmail.com>
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Subject: Re: [9fans] signal.h in APE for newbies
Topicbox-Message-UUID: dac7004a-ead3-11e9-9d60-3106f5b1d025

> When I trigger a division by zero the handler is not called, I just
> get trap 19 message.

if i do a floating-point division by zero, the SIGFPE signal handler is called,
because ape's signal recognises the initial "sys: fp: ".  (ie, it works for me.)

it doesn't work for an integer division by zero, which produces a different message for the underlying notify:

8.out 205840: suicide: sys: trap: divide error pc=0x00001089

but that's fine too! Linux's signal(2) says, apparently referring to POSIX rules:

        ....  Integer division by zero  has  undefined  result.
       On some architectures it will generate a SIGFPE signal.  (Also dividing
       the most negative integer by -1 may generate  SIGFPE.)   Ignoring  this
       signal might lead to an endless loop.

Linux might not be particularly good at documenting this particular area,
so perhaps the standard(s) have useful hints or advice that APE could follow.