On 20/04/2011 4:06 PM, Sascha Vieweg wrote:
Hello R experts
I am googling and reading around, however, I can't get it working
(perhaps because I do not understand much C, however, I'll give it
a try). I am trying to include C++ code into an R routine, where
the C++ code looks:
#include<iostream>
using namespace std;
void foo (double* x, double* y, double* out)
{
out[0] = x[0] + y[0];
}
Back in R, the command
R CMD SHLIB --preclean -o xplusy
works fine resulting in two new files, xplusy.o and xplusy.so. The
wrapper in R is:
dyn.load("xplusy.so")
xplusy<- function(x, y){
.C("foo", as.double(x), as.double(y), out=double(1))$out
}
xplusy(1, 2)
dyn.unload("xplusy.so")
Now, dyn.load() works and xplusy also shows up in getLoadedDLLs().
However, when invoking the function, xplusy(1, 2), R complains:
Error in .C("foo", as.double(x), as.double(y), out = double(1)): C
symbol name "foo" not in load table
I found some hints concerning Fortran code producing this error
message, but no help concerning C code.
You have C++ code, not C code. C++ normally mangles names of exports.
To get this to work, you should surround your declarations with
extern "C" {
}
Another possibility is to use the Rcpp package; it writes the interface
code for you.
Duncan Murdoch
Any help tips?
Thanks, *S*
$. uname -a
Darwin * 10.7.3 Darwin Kernel Version 10.7.3[...]
$: c++ --version
i686-apple-darwin10-g++-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5666)
(dot 3)
platform i386-apple-darwin9.8.0
arch i386
os darwin9.8.0
system i386, darwin9.8.0
status
major 2
minor 12.2
year 2011
month 02
day 25
svn rev 54585
language R
version.string R version 2.12.2 (2011-02-25)
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