[Rd] Problem with shared library and lapack under windows

Prof Brian Ripley ripley at stats.ox.ac.uk
Thu Jun 4 19:33:44 CEST 2015

On 03/06/2015 08:48, bstr wrote:
> Hi all,
> I have a C function, say Cfun, that calls Lapack's DGEMM routine and I need
> to create a shared library to use Cfun inside R. The C file is the following
> #include<stdio.h>
> #include<R.h>
> #include<R_ext/Lapack.h>
> void Cfun(double *res, double *X, int *n, int *q)
> {
> 	char *ptr_TRANSA, TRANSA='T', *ptr_TRANSB, TRANSB='N';
> 	double *ptr_ALPHA, ALPHA=1.0, *ptr_BETA, BETA=0.0;
> 	ptr_ALPHA=&ALPHA;
> 	ptr_BETA=&BETA;
> 	dgemm_(ptr_TRANSA, ptr_TRANSB, q, q, n, ptr_ALPHA, X, n, X, n, ptr_BETA,
> res, q);
> }
> In Ubuntu I have no problem in compiling:  R CMD SHLIB -llapack myfile.c.
> However, under Windows the -llapack flag is not recognised and I am able to
> get the code compiled only if I build an R package with the suitable
> Makevars file options: PKG_LIBS=$(LAPACK_LIBS) $(FLIBS). Is there a way to
> get the .dll without resorting to build a package?

SHLIB reads a Makevars file ....  The manual says so right at the top of 
the section 
http://cran.r-project.org/doc/manuals/r-release/R-exts.html#Using-Makevars .

> Thanks in advance,
> N. Lunardon

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford
1 South Parks Road, Oxford OX1 3TG, UK

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