From: Charles Forsyth <forsyth@terzarima.net>
To: fernanbolando@mailc.net, 9fans@9fans.net
Subject: Re: [9fans] signal.h in APE for newbies
Date: Fri, 4 Jul 2008 10:59:30 +0100 [thread overview]
Message-ID: <ac4210fe8560e9c8511064fefd908a10@terzarima.net> (raw)
In-Reply-To: <1d5d51400807040117i242cae83y6d65e8972748ea47@mail.gmail.com>
> 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.
next prev parent reply other threads:[~2008-07-04 9:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-04 8:17 Fernan Bolando
2008-07-04 9:59 ` Charles Forsyth [this message]
[not found] ` <a85d07977219d1010dd930280d4b013e@terzarima.net>
2008-07-04 14:17 ` Fernan Bolando
2008-07-04 15:54 ` Russ Cox
2008-07-04 17:19 ` Charles Forsyth
2008-07-04 17:21 ` erik quanstrom
2008-07-04 18:04 ` Charles Forsyth
2008-07-04 18:14 ` erik quanstrom
2008-07-04 19:22 ` Russ Cox
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