l term from a string and calls it.

int
call_chars(const char *goal)
{ fid_t fid = PL_open_foreign_frame();
  term_t g = PL_new_term_ref();
  BOOL rval;

  if ( PL_chars_to_term(goal, g) )
    rval = PL_call(goal, NULL);
  else
    rval = FALSE;

  PL_discard_foreign_frame(fid);
  return rval;
}
  ...
  call_chars("consult(load)");
  ...