This is an internal function that is called from R's C code to
determine the enclosing namespace of a
.C
/.Call
/.Fortran
/.External
call which has
no PACKAGE
argument. If the call has been made from a function
within a namespace, then we can find the DLL associated with that
namespace. The purpose of this is to avoid having to use the
PACKAGE
argument in these native calls and so better support
versions of packages.
This is an internal function that may be migrated to internal C
code in the future and so should not be used by R programmers.