[CMake] Please support FindLAPACK/FindBLAS for C/C++-only projects

[Mark Moll]

On Jan 21, 2010, at 10:22 AM, Jed Brown wrote:

> On Thu, 21 Jan 2010 09:17:22 -0600, Mark Moll <mmoll at cs.rice.edu> wrote:
>> You *can* use the Fortran BLAS/LAPACK libraries with C/C++ code.
> 
> Yes, this is actually very common, but check_fortran_function_exists
> works by trying to link an actual Fortran program.  When calling from C,
> you have to know how Fortran names are mangled which means testing a
> number of common choices.  Nobody put this logic into these Find
> modules, but it would be nice because many (most?) users of BLAS/Lapack
> need to call it from both Fortran and C so they need to know how the
> symbols are mangled.  CBLAS/CLapack are entirely different beasts, but I
> know of far more C projects that call the Fortran versions directly than
> use the C bindings.


Wouldn’t it be possible to use “nm” to detect the Fortran name mangling? For example:

On OS X, default LAPACK library:
> nm /usr/lib/liblapack.dylib | grep cheev$ | awk '{print $3}’
_cheev

On Linux, using MKL:
> nm /opt/intel/Compiler/11.1/056/mkl/lib/em64t/libmkl_intel_lp64.a | grep cheev$ | awk '{print $3}'
cheev

(Of course the “grep” and “awk” commands can be replaced with some cmake string commands, if you want to make it a bit more portable.)

-- 
Mark