Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!sdd.hp.com!apollo!rehrauer
From: rehrauer@apollo.HP.COM (Steve Rehrauer)
Newsgroups: comp.sys.apollo
Subject: Re: BUG in cc int>double type conversion !!!!!
Keywords: bug cc double type conversion
Message-ID: <4c13efca.20b6d@apollo.HP.COM>
Date: 8 Aug 90 14:48:00 GMT
References: <538@al.ele.tue.nl>
Sender: root@apollo.HP.COM
Reply-To: rehrauer@apollo.HP.COM (Steve Rehrauer)
Organization: Hewlett-Packard Apollo Division - Chelmsford, MA
Lines: 45

In article <538@al.ele.tue.nl> jos@ele.tue.nl (Jos van Eijndhoven) writes:
>I just discovered a bug in the apollo 10.2 C compiler on a DN3000,
>regarding int to double type conversion between two fields in a union.
>The problem is shown by the following tiny program:
>
>/****** show cc bug in union type conversion *****/
>#include <stdio.h>
>main()
>{	union
>	{	int i;
>		double f;
>	} val;
>	double f;
>
>	val.i = 1;
>
>	f = (double)(val.i);
>	val.f = (double)(val.i);
>	printf("f = %g, val.f = %g\n", f, val.f);
>}
>/**************************************************/
>
>The program will print two different values!!!
>Changing the order of int and double in the union doesn't help.
>Changing the union to a struct removes the error.
>
>I am severely hindered by this bug in a larger program.
>Is this problem known already, and if so is there a patch available?
>Does anybody know an easy way to circumvent the problem?

Jos, I've verified that the bug exists in 6.7 C, and that it is fixed
in 6.8.  The 6.8 C compiler belongs to what we're internally calling
the "CR1.0" compiler release, and is currently in Beta test.  Gee,
it'd be nice if you volunteered to be a CR1.0 Beta site! :-)

However, more realistically, there is also a patched 6.7 C that fixes
this problem.  Ask your friendly neighborhood customer-service rep for
the latest 6.7 C compiler, referred to internally as "1989.1 plus".

>Any help appreciated,

You're welcome.
--
   >>"Aaiiyeeee!  Death from above!"<<     | (Steve) rehrauer@apollo.hp.com
"Spontaneous human combustion - what luck!"| Apollo Computer (Hewlett-Packard)