Re: order of libraries in Makefiles

[Martin Helm]

On Montag, 1. August 2011 20:55:14 Sergei Steshenko wrote:
> 
> 'configure' was run using the attached autogenerated 'config_wrapper.sh'
> script.
> 
> And regarding BLAS_LIBS:
> 
> "
> address@hidden:~/junk> grep BLAS_LIBS
> /mnt/sdb8/sergei/AFSWD_debug/build/octave-3.4.2/config.log
> BLAS_LIBS='-lcblas -lf77blas -latlas'
> address@hidden:~/junk>
> ".
> 
> I didn't give the above order of libraries manually.
> 
> By the way, I've added a piece of code that makes BLAS_LIBS everywhere
> look this way:
> 
> BLAS_LIBS = -latlas -lcblas -lf77blas
> 
> and am currently rebuilding.
> 
> Regards,
>   Sergei.
I think your assumption is wrong and also your conclusion. You fixed here 
something which does not have to be fixed. Why? The libraries in question cblas 
and f77blas (and also atlas of course) ARE ALL actually the optimized atlas 
libraries if your library path is correctly set and not the generic slow ones. 
So it makes absolutely no difference that you changed their order.
Take a look at the atlas documentation to see and understand what cblas and 
f77blas really is in atlas.
If you want more control you should not manipulate the resulting configuration 
but pass the libraries in the order you want to the configure script.
This is an arbitrary example from my machine
./configure \
     --with-blas="-L/usr/lib64/atlas -lptf77blas -lptcblas -latlas" \
     --with-lapack="-L/usr/lib64/atlas -llapack"

If you wonder what the ptcblas and the ptf77blas is, this are simply the multi 
threaded counterparts to the single threaded cblas and f77blas for SMP 
machines.