Function libR_sys::R_RegisterCCallable

pub unsafe extern "C" fn R_RegisterCCallable(
    package: *const c_char,
    name: *const c_char,
    fptr: DL_FUNC
)

Interface for exporting and importing functions from one package for use from C code in a package. The registration part probably ought to be integrated with the other registrations. The naming of these routines may be less than ideal.