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X-Authentication-Warning: hp2.xraylith.wisc.edu: khan owned process doing -bs
Date: Tue, 23 Jan 2001 21:09:48 -0600 (CST)
From: Mumit Khan <khan AT NanoTech DOT Wisc DOT EDU>
To: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>
Subject: g77 -lm link problem [Re: Results for 2.97 20010115 (experimental) testsuite on i686-pc -cygwin]
In-Reply-To: <20010123211050.A22516@redhat.com>
Message-ID: <Pine.HPP.3.96.1010123210154.6114K-100000@hp2.xraylith.wisc.edu>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Tue, 23 Jan 2001, Christopher Faylor wrote:

> On Wed, Jan 24, 2001 at 12:38:56AM -0000, Billinghurst, David (CRTS) wrote:
> 
> I guess I was vainly hoping that someone would actually debug the
> problem or offer insight into the reason for the problem rather than
> saying "Just remove -lm! Works for me!"

The problem is that the g77 runtime library (libg2c) contains main, and
internal reordering of libraries by gcc driver causes the problem.

  $ cat libm-bugf.f

        program libm_bug
        write (*,*) 'libm bug'
        stop
        end
  
Following causes a problem because g77 driver puts -lm before -lg2c
(use -v to see it):

  $ g77 -o libm-bugf.exe libm-bugf.f -lm
  /usr/lib/libm.a(libcmain.o)(.text+0x6a):libcmain.c: undefined reference 
  to `WinMain AT 16' collect2: ld returned 1 exit status

Following "fixes" the problem now that we know that libg2c must come
beforehand (use -v to see it):

  $ g77 -o libm-bugf.exe libm-bugf.f -lg2c -lm
  $ 

I know the symptom, but don't know the real problem, hence don't know
the solution (yet).

Regards,
Mumit



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