Returnin char back through the .Call interface

On Wed, 4 Feb 2004, wolski wrote:

Hi!

My results or error messages are copied in a string and than have to be
passed back through the .Call interface togheter with numeric results
What is the best way to allocate storage to a character? (R_alloc?) And
how to add it to a list? (e.g. allocVector(VECSXP, 9))


Help are highly appreciated.

Again, browsing the header files usually helps. A short and probably not 
ideal example (COPY_TO_USER_STRING() does the work):

SEXP R_G_get_gisrc_file() {
     SEXP ans;
     char *gisrc;
     
     PROTECT(ans=NEW_CHARACTER(1));
     gisrc = G__get_gisrc_file();
     if (gisrc) {
   gisrc = G_store(gisrc);
          SET_STRING_ELT(ans, 0,
               COPY_TO_USER_STRING(gisrc));
     } else {
          SET_STRING_ELT(ans, 0,
               COPY_TO_USER_STRING("empty"));
      }
     UNPROTECT(1);
     return(ans);
}

Eryk



Ps.
I tried a with mkChar
and with
PROTECT(ral1 = NEW_CHARACTER(1));