go back to using dataptr()

Author: Enchufa2

ChangeLog

@@ -1,7 +1,7 @@
 2026-03-26  Iñaki Ucar <iucar@fedoraproject.org>
 
-	* inst/include/Rcpp/internal/r_vector.h: Return null start for empty vectors
-	instead of an invalid pointer, which causes UB in e.g. std::copy
+	* inst/include/Rcpp/internal/r_vector.h: Use dataptr() again to avoid an
+	invalid pointer for empty vectors, which causes UB in e.g. std::copy
 	* inst/tinytest/test_vector.R: Add tests for std::copy
 	* inst/tinytest/cpp/Vector.cpp: Idem
 

inst/include/Rcpp/internal/r_vector.h

@@ -33,23 +33,6 @@ typename Rcpp::traits::storage_type<RTYPE>::type* r_vector_start(SEXP x) {
     return reinterpret_cast<pointer>(dataptr(x));
 }
 
-// add specializations to avoid use of dataptr
-#define RCPP_VECTOR_START_IMPL(__RTYPE__, __ACCESSOR__)                                              \
-    template <>                                                                                      \
-    inline typename Rcpp::traits::storage_type<__RTYPE__>::type* r_vector_start<__RTYPE__>(SEXP x) { \
-        if (Rf_xlength(x) == 0)                                                                      \
-            return NULL;                                                                             \
-        return __ACCESSOR__(x);                                                                      \
-    }
-
-RCPP_VECTOR_START_IMPL(LGLSXP,  LOGICAL);
-RCPP_VECTOR_START_IMPL(INTSXP,  INTEGER);
-RCPP_VECTOR_START_IMPL(RAWSXP,  RAW);
-RCPP_VECTOR_START_IMPL(CPLXSXP, COMPLEX);
-RCPP_VECTOR_START_IMPL(REALSXP, REAL);
-
-#undef RCPP_VECTOR_START_IMPL
-
 /**
  * The value 0 statically casted to the appropriate type for
  * the given SEXP type