From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29412 invoked by alias); 23 Dec 2002 10:26:03 -0000 Mailing-List: contact gcc-prs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-prs-owner@gcc.gnu.org Received: (qmail 29397 invoked by uid 71); 23 Dec 2002 10:26:02 -0000 Date: Mon, 23 Dec 2002 02:26:00 -0000 Message-ID: <20021223102602.29395.qmail@sources.redhat.com> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, From: Warren du Plessis Subject: Re: other/8974: fabs error with -ansi Reply-To: Warren du Plessis X-SW-Source: 2002-12/txt/msg01229.txt.bz2 List-Id: The following reply was made to PR other/8974; it has been noted by GNATS. From: Warren du Plessis To: bangerth@dealii.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org, warren@eng.up.ac.za, gcc-gnats@gcc.gnu.org Cc: Subject: Re: other/8974: fabs error with -ansi Date: Mon, 23 Dec 2002 12:25:15 +0000 Hi, If I try to link with "-static -ansi -lm" I get the following error message: /tmp/cc6IBIGC.o: In function `main': /tmp/cc6IBIGC.o(.text+0x43): undefined reference to `fabs' /tmp/cc6IBIGC.o(.text+0x89): undefined reference to `fabs' /tmp/cc6IBIGC.o(.text+0xca): undefined reference to `fabs' collect2: ld returned 1 exit status If I remove the -ansi flag and compile with "-static -lm" everything works perfectly as I explained previously. I tried compiling with -O through -O8 (just to make sure! - I know the docs say that there is nothing above -O3, but a friend of mine says that it goes up to -O5 or -O6 at least) and got exactly the same results. My friend says that it could be a typecasting problem if that helps. Thanks for your help! Warren bangerth@dealii.org wrote: >Synopsis: fabs error with -ansi > >State-Changed-From-To: open->feedback >State-Changed-By: bangerth >State-Changed-When: Fri Dec 20 19:37:38 2002 >State-Changed-Why: > The problem you write seems as if for certain numbers the > implementation of fabs is doing something wrong, but only > on certain machines. Now, fabs is a function that libm > implements, not the compiler, so to find out where the > problem lies exactly, try the following: > > - try linking with -static on a machine where it works. > This makes sure that not the local libm is taken, but the > one from the system where it works. Try the other way > round and see whether it then also fails on the machines > it worked on previously. > - Try what happens when you switch on optimization. > > Just for the reference, I cannot reproduce the problem > on a PIII, but that was to be expected from your report. > > Thanks > Wolfgang > >http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8974 > > > >