Linking Rblas [under Windows]

-----Original Message-----
From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk] 
Sent: Thursday, March 09, 2006 12:09 PM
To: Rau, Roland
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] Linking Rblas [under Windows]

Yes, lots of packages link to Rblas.  The help page for SHLIB 
tells you

      Please consult section 'Creating shared objects' in the manual
      'Writing R Extensions' for how to customize it (for 
example to add
      'cpp' flags and to add libraries to the link step) and 
for details
      of some of its quirks.

so it should not have been at all hard to find the information.

A portable way would be to have a file Makevars containing

PKG_LIBS=$(BLAS_LIBS)

Note that your precise example will not work in R-2.3.0 when it is 
released, whereas the portable form will.  (In fact it only works in 
R-2.2.0 if you have previously make libRblas.a.)

On Thu, 9 Mar 2006, Rau, Roland wrote:

Dear all,

when making a DLL via Rcmd SHLIB is there a way to link against a
library such as Rblas (I am on a Windows platform) on a case to case
basis?

I played a bit around with some self-written C-code which 

should call

the function 'dasum' defined in Blas.h.
I encountered the following problem:

u:\codeplay>Rcmd SHLIB mysumming.c
Rcmd SHLIB mysumming.c
gcc  --shared -s  -o mysumming.dll mysumming.def mysumming.a
-LU:/R/R-2.2.0/src/gnuwin32   -lg2c -lR
mysumming.a(mysumming.o)(.text+0x1b):mysumming.c: undefined 

reference to

`dasum_'
collect2: ld returned 1 exit status
make: *** [mysumming.dll] Error 1

My (very limited) knowledge on C tells me that the function 'dasum'
is actually defined (due to #include <R_ext/BLAS.h> in my 

C-file) but

it needs to be linked against the correct library during the linking
procedure. I guess the correct library should be Rblas.dll since I
could do it "by hand" calling gcc like this:

gcc  --shared -s  -o mysumming.dll mysumming.def mysumming.a
-LU:/R/R-2.2.0/src/gnuwin32   -lg2c -lR -lRblas

and it worked.

Thank you very much for your help in advance.
If you need more details such as the C-Code, the R-Code 

calling C, ..:

just let me know.

Thanks,
Roland

version

        _
platform i386-pc-mingw32
arch     i386
os       mingw32
system   i386, mingw32
status
major    2
minor    2.0
year     2005
month    10
day      06
svn rev  35749
language R

u:\codeplay>gcc --version
gcc --version
gcc (GCC) 3.4.2 (mingw-special)
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying 

conditions.  There is

NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

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