[Rd] R CMD check error (interfacing to C API of other pkg): Solved

[Therneau, Terry M., Ph.D.]

Martin,
   That was it-  I forgot the "LinkingTo" line.  I had read that section of the manual 
twice in the last 2 days, yet somehow missed that critical line both times.  And even 
worse, the final sentence of said section references my own coxme package as an example of 
how to do it correctly!

Thank you all for the help.  My only remaining defense, but a very weak one, is that the 
error message could have been better since it led me to believe that R couldn't find the 
library at all.

Terry Therneau

On 02/10/2017 10:26 AM, Martin Maechler wrote:
>>>>>> Therneau, Terry M , Ph D <therneau at mayo.edu>
>>>>>>      on Thu, 9 Feb 2017 12:56:17 -0600 writes:
>
>      > Martyn,
>      > No, that didn't work.
>      > One other thing in the mix (which I don't think is the issue) is that I call one of the
>      > C-entry points of expm.  So the DESCRIPTION file imports expm, the NAMESPACE file imports
>      > expm, and the init.c file is
>
>      > #include "R.h"
>      > #include "R_ext/Rdynload.h"
>
>      > /* Interface to expm package. */
>      > typedef enum {Ward_2, Ward_1, Ward_buggy_octave} precond_type;
>      > void (*expm)(double *x, int n, double *z, precond_type precond_kind);
>      > void R_init_hmm(DllInfo *dll)
>      > {
>      >      expm = (void (*)) R_GetCCallable("expm", "expm");
>      > }
>
>      > I don't expect that this is the problem since I stole the
>      > above almost verbatim from the msm package.
>
>      > Terry T.
>
> Hmm.  Yes, I can see that the CRAN package  msm  does do this, indeed.
>
> It is interesting if/why that does not produce any notes or rather even warnings.
> In principle, if you use the C API of 'expm'  you should use
>    'LinkingTo: expm'
>
> see *the* manual, specifically the section
>
>      https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Linking-to-native-routines-in-other-packages
>
> and that section does mention that (unfortunately in my view)
> you also should use 'Imports:' or 'Depends:' in addition to the 'LinkingTo:'
>
> Note howver that  'expm' would not have to mentioned
> in the NAMESPACE file.... unless your R functions do use some of
> expm's R level functionality.
>
>
> Martin
>