Rinternals.h and undefined symbols

On 3/19/2007 8:55 PM, Ernest Turro wrote:

On 20 Mar 2007, at 00:50, Duncan Murdoch wrote:

On 3/19/2007 8:41 PM, Ernest Turro wrote:

On 20 Mar 2007, at 00:18, Duncan Murdoch wrote:

On 3/19/2007 7:41 PM, Ernest Turro wrote:

On 19 Mar 2007, at 21:32, Duncan Murdoch wrote:

On 3/19/2007 5:23 PM, Ernest Turro wrote:

Hi,
I'm trying to register my native routines using
R_registerRoutines  (...). I can compile the code, but the
loader cannot resolve the  symbol:
undefined symbol:
_Z18R_registerRoutinesP8_DllInfoPK12R_CMethodDefPK15R_CallMethodD
ef S3 _S6 _
$ nm bgx.Rcheck/bgx/libs/bgx.so | grep R_registerRoutines
                  U
_Z18R_registerRoutinesP8_DllInfoPK12R_CMethodDefPK15R_CallMethodD
ef S3 _S6 _
Why does it have this funny name? If I look at libR.so, I get
an   ordinary symbol name:

That looks like C++ name mangling.  Are you wrapping your
declarations in

extern "C" { }

?

Yeah, the routine is literally just:
extern "C"
   void R_init_bgx(DllInfo *info) {
     R_registerRoutines(info, cMethods,NULL,NULL,NULL);
   }
with cMethods declared outside as a static const R_CMethodDef.

I'm no C++ expert, but that looks like it declares R_init_bgx to
be  a "C" routine, but not R_registerRoutines (which is what the
error  was about).  Its declaration is in Rdynload.h:

#ifdef __cplusplus
extern "C" {
#endif
int R_registerRoutines(DllInfo *info, const R_CMethodDef * const
croutines,
		       const R_CallMethodDef * const callRoutines,
		       const R_FortranMethodDef * const fortranRoutines,
                       const R_ExternalMethodDef * const
externalRoutines);

Rboolean R_useDynamicSymbols(DllInfo *info, Rboolean value);
#ifdef __cplusplus
}
#endif

so maybe your compiler doesn't define __cplusplus, or you didn't
include R_ext/Rdynload.h?

Duncan, you hit the nail on the head. Thanks so much.

If you download R-2.4.1.tar.gz from CRAN you will find that the
extern "C" is missing in Rdynload.h! I added it to my copy and my
code compiles now. I wonder why it's missing. Has this been fixed in
cvs?

Yes, it's a new addition Duncan Temple Lang added in November.  I didn't
remember that or I would have mentioned it.

Duncan Murdoch

Thanks,

Ernest

PS. you don't need the braces after extern "C"

Thanks for the reply.
__cplusplus is defined and I do #include <R_ext/Rdynload.h>
(after  all, it does compile)...
I've tried this on two different machines, so it's not a problem
specific to my setup either...  ):

Here I'm just guessing:  you don't wrap the whole function in
extern "C", you just put extern "C" ahead of its header. That's not
the usual way it's done, but I don't know C++ well enough to know
if it matters. Nevertheless, I'd try

 extern "C" {
    void R_init_bgx(DllInfo *info) {
      R_registerRoutines(info, cMethods,NULL,NULL,NULL);
    }
 }

just to see if it helps.

Duncan Murdoch