[R-pkg-devel] Compiled code should not call non-API entry points in R

[Andrew Simmons]

Hi everyone,


I had some R code for dealing with connections, and I was using
summary.connection(). I rewrote it in C, so I was doing something more
like:

#include <R_ext/Connections.h>

Rconnection Rcon = R_GetConnection(file);
Rcon->description or Rcon->class

but now, when checking my package, I get the following note:

* checking compiled code ... NOTE
File 'this.path/libs/x64/this.path.dll':
  Found non-API call to R: 'R_GetConnection'

Compiled code should not call non-API entry points in R.

See 'Writing portable packages' in the 'Writing R Extensions' manual.

This isn't surprising, <R_ext/Connections.h> (seen here:
https://github.com/wch/r-source/blob/50ff41b742a1ac655314be5e25897a12d3096661/src/include/R_ext/Connections.h#L21)
says that it is not part of the R API, and later on says that it is
subject to change without notice or backwards compatibility.

R_GetConnection was added in R 3.3.0, so I added "Depends: R (>=
3.3.0)" to my DESCRIPTION, then I added something like this to my
header:

#if !defined(R_CONNECTIONS_VERSION)
    #error why is R_CONNECTIONS_VERSION not defined????
#elif R_CONNECTIONS_VERSION == 1
    extern Rconnection R_GetConnection(SEXP sConn);
#else
    #error this.path is only implemented for R_CONNECTIONS_VERSION 1
#endif

but the NOTE still remains. I think I've taken all the precautions I
can, is there anything more I can do? Will I be unable to submit the
update for my package? Will the CRAN team ignore the NOTE if I explain
the precautions I added?