From mboxrd@z Thu Jan  1 00:00:00 1970
From: Karthik Vishwanath <karthik@northstar.dartmouth.edu>
Subject: Re: undefined sqrt()
Date: Thu, 24 Oct 2002 17:50:25 -0400
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To: "Theo. Sean Schulze" <tschulze@teamfinders.org>
Cc: linux-c-programming@vger.kernel.org

from the gcc man page: 

"
        ... The linker handles an archive file by scan-
        ning  through  it  for members which define symbols
        that have so far been referenced but  not  defined.
"

The funtion sqrt() is defined in the libm.a and declared in <math.h>. To
use the function, you need the "real code" (which is in libm.a). Thats the
way I think about it. I'll let the gurus on this list clarify, if anything
is misleading/ misrepresented here. 

-K


On Thu, 24 Oct 2002, Theo. Sean Schulze wrote:

> Thanks.  The "-lm" did it.  Why?  I see from the gcc man page that the
> "-l" is a linker option.  Am I right that the linker then searches for
> "libm.a"?  Again, why, if I am right, would it need to after I
> included math.h?  Isn't sqrt() in math.h?
> 
> Thanks,
> Sean
> 
> On Thu, Oct 24, 2002 at 04:17:27PM -0400, Karthik Vishwanath hunted and pecked out:
> > Try:
> > 
> > gcc -Wall -lm -o glide glide.c
> > 
> > -K
> >