All,
I am still having trouble dyn.load'ing some code into R. I have
isolated the problem, I wonder if someone could explain what I am
seeing.
I think the problem is that a symbol defined in my compiled code
clashes with one already defined in R. The result is that the function
in my code is not called. Here is an example
// lnktst.cc
extern "C"
{
void func(double *out1, double *out2);
void dnrm2_(double *out);
void dnrm3_(double *out);
}
void func(double *out1, double *out2)
{
dnrm2_(out1);
dnrm3_(out2);
}
void dnrm2_(double *out)
{
*out = 1234.5;
}
void dnrm3_(double *out)
{
*out = 6789.0;
}
// End of lnktst.cc
When I compile:
g++ -shared -static -o lnktst.so lnktst.cc
and then in R I call "func"
> dyn.load("lnktst.so")
> .C('func', double(1), double(1))
[[1]]
[1] 0
[[2]]
[1] 6789
So, as you can see, the function "dnrm2_" is not called whereas "dnrm3_"
is, even though both functions are identical in form. Now, I believe
dnrm2_ is a BLAS function, and so it is likely R already has a copy
floating around. However, it surprises me that the "-static" option does
not force the call in my code to "dnrm2_" to be linked to the function
defined in my code.
I have been writing C code for Splus for quite a while and don't recall
ever running across this issue. However, I am new to R, so I wonder, am
I missing something obvious?
I am running this on Ubuntu Linux, the output of uname -a is:
Linux calder-linux 2.6.22-14-generic #1 SMP Sun Oct 14 23:05:12 GMT 2007 i686
GNU/Linux
Thanks for any help,
Matt
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