From octave-maintainers-request at bevo dot che dot wisc dot edu Mon Nov 17 01:35:10 2003
Subject: LAPACK dll
From: pkienzle at users dot sourceforge dot net
To: octave-maintainers mailing list <octave-maintainers at bevo dot che dot wisc dot edu>
Date: Mon, 17 Nov 2003 02:38:26 -0000

Hi,

I've been trying to put together a Windows version of
Octave with an lapack DLL so that we only need to
provide atlas-enhanced replacements for lapack.dll
instead of the entire libcruft.dll.

I have run into a snag --- octave wants to override xerbla
at runtime, but windows wants to statically link it into
the DLL, or at least it wants a DLL containing xerbla
that it can link to.

Is there a way to override xerbla at runtime?

What I'm doing currently is replacing xerbla with 
one which calls privstop instead of stop, where
privstop() is a C function which calls (*stopfn)().
stopfn is defined by a call to stopblas(xstopx).  This
should work (I haven't rebuilt octave yet), but it means 
I need to convince octave to call stopblas(xstopx) on 
windows.

There are two things I don't like about this solution:

1) The octave specific hack to lapack --- I want a
unified lapack useable by all the windows scientific
packages so that we can share the work of building
the optimized versions.  Any idea how R/Matlab/Scilab, 
etc. address this problem?  Or do the just assume
that xerbla is never invoked?

2) The windows specific hack to octave.  That's minor
enough that I can get over it, but it is inelegant at best.

I'm attaching the build code and support functions
for mklapackdll.sh for the curious.  I had to hack
around a few more things to avoid loading the libg2c
I/O functions.

Thanks in advance,

Paul Kienzle
pkienzle at users dot sf dot net