From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-return-10480-listarch-gdb=sourceware.cygnus.com@sources.redhat.com>
Received: (qmail 21788 invoked by alias); 20 Sep 2002 22:04:55 -0000
Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm
Precedence: bulk
List-Subscribe: <mailto:gdb-subscribe@sources.redhat.com>
List-Archive: <http://sources.redhat.com/ml/gdb/>
List-Post: <mailto:gdb@sources.redhat.com>
List-Help: <mailto:gdb-help@sources.redhat.com>, <http://sources.redhat.com/ml/#faqs>
Sender: gdb-owner@sources.redhat.com
Received: (qmail 21779 invoked from network); 20 Sep 2002 22:04:55 -0000
Received: from unknown (HELO crack.them.org) (65.125.64.184)
  by sources.redhat.com with SMTP; 20 Sep 2002 22:04:55 -0000
Received: from nevyn.them.org ([66.93.61.169] ident=mail)
	by crack.them.org with asmtp (Exim 3.12 #1 (Debian))
	id 17sWpF-0001RU-00; Fri, 20 Sep 2002 18:04:41 -0500
Received: from drow by nevyn.them.org with local (Exim 3.35 #1 (Debian))
	id 17sVtE-0000iw-00; Fri, 20 Sep 2002 18:04:44 -0400
Date: Fri, 20 Sep 2002 15:04:00 -0000
From: Daniel Jacobowitz <drow@mvista.com>
To: Peter Jay Salzman <p@dirac.org>
Cc: Gdb Mailing List <gdb@sources.redhat.com>
Subject: Re: another conditional breakpoint question
Message-ID: <20020920220444.GA2765@nevyn.them.org>
Mail-Followup-To: Peter Jay Salzman <p@dirac.org>,
	Gdb Mailing List <gdb@sources.redhat.com>
References: <20020920201304.GA29419@dirac.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20020920201304.GA29419@dirac.org>
User-Agent: Mutt/1.5.1i
X-SW-Source: 2002-09/txt/msg00323.txt.bz2

On Fri, Sep 20, 2002 at 01:13:04PM -0700, Peter Jay Salzman wrote:
> in the program:
> 
>    #include <math.h>
>    int main(void)
>    {
>         double i = 0.0;
>         double j = cos(i);
>         return 0;
>    }
> 
> i set a breakpoint which should never be reached:
> 
> p@satan% gdb mymath
> (gdb) break main if cos(0.0) > 1000.0
> Breakpoint 1 at 0x8048426: file mymath.c, line 5.
> 
> (gdb) run
> Breakpoint 1, main () at mymath.c:5
> 5               double i = 0.0;
> 
> considering that cosine should be greater than 1 for a real variable,
> this is quite strange!
> 
> 
> i don't know if this is related, but i notice that cos(0) doesn't have a
> value of 1.0.  not even close:
> 
>    (gdb) p cos(0)
>    $3 = 14368
> 
> but just in case gdb doesn't know that cos() returns a double, i also
> tried:
> 
>    (gdb) p/f cos(0.0)
>    $1 = 2.00890148e-41
> 
> neither of these are even close to being right.
> 
> 
> can someone tell me why gdb is reaching that breakpoint which should
> never be reaced?  and is there any way of getting gdb to tell me that
> cos(0) is supposed to be equal to 1?   :*)

You don't have debug information in your libraries.  Try:

(gdb) ptype cos

to see what I mean.  You need debugging info if you want that to wokr.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer