[cffi-devel] detecting int size used by library

[Mark Hoemmen]

On Wed, May 26, 2010 at 05:42, Tamas K Papp <tkpapp at gmail.com> wrote:
> I am using LAPACK/BLAS (ATLAS) libraries via CFFI.  Recently, my
> tests failed, and to my surprise, the solution was to use 32-bit ints.
> Note that I am on a 64-bit platform, using the Ubuntu libraries, so
> why this happens is a mystery.  But it would be great if I could
> detect it somehow from within Lisp.

In the particular case of LAPACK and the BLAS: the default LAPACK and
BLAS should always use 32-bit ints (Fortran's INTEGER type, a.k.a.
"INTEGER(4)").  There are versions of both libraries that use 64-bit
ints ("INTEGER(8)"), but the system should always identify them
specially: either as separate, differently named libraries, or as
differently named functions within the same library.  (I've seen both
possibilities.)

In general: Of course it would be nicer to be able to do everything in
Lisp, but have you taken a look at CMake's CheckTypeSize module?

http://www.cmake.org/cmake/help/cmake-2-8-docs.html#module:CheckTypeSize

mfh