Fine tuning gcc build to machine specific properties

Brian Dessent
Mon Sep 3 10:21:00 GMT 2007

Ted Byers wrote:

> tests using the high performance library passed.  Now,
> doing exactly the same thing, make dies half way
> through at link time for one of the tests half way
> through make complaining that -lg2c doesn't exist.
> But it does, obviously, since make using gcc v 3.4.4
> found it.  Where do I look for a fix to this?  gcc v
> 3.4.4 must have had something hard coded into it to
> tell it where this library is, because I didn't tell
> it where to look.  I didn't even know this library
> existed the first time I built the AMD acml examples.
> My guess, from what I saw today, is that my current
> build of gcc v 4.2.1 doesn't have this information
> built in.  I assume that is this information was in
> either environment variables or in the GnuMakefile, my
> attempt at compiling the examples using gcc v 4.2.1
> would have succeeded.

libg2c was part of g77 but g77 no longer exists in gcc 4.x, it was
replaced by the much more modern gfortran.  It's not a matter of not
finding the library, it just doesn't exist.  I'd say it's a bug in the
Makefile for assuming gcc 3.x.  The fortran list will be able to give
you more details.


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