diff --git a/test/testpkg/src/add.c b/test/testpkg/src/add.c
index 77cd5f3..1bc5036 100644
--- a/test/testpkg/src/add.c
+++ b/test/testpkg/src/add.c
@@ -3,8 +3,8 @@
 
 SEXP add(SEXP a, SEXP b)
 {
-  SEXP result = PROTECT(allocVector(REALSXP, 1));
-  REAL(result)[0] = asReal(a) + asReal(b);
+  SEXP result = PROTECT(Rf_allocVector(REALSXP, 1));
+  REAL(result)[0] = Rf_asReal(a) + Rf_asReal(b);
   UNPROTECT(1);
   return result;
 }
diff --git a/test/testpkg/src/subtract.cpp b/test/testpkg/src/subtract.cpp
index c9ef0a1..175043d 100644
--- a/test/testpkg/src/subtract.cpp
+++ b/test/testpkg/src/subtract.cpp
@@ -3,8 +3,8 @@
 
 extern "C" SEXP subtract(SEXP a, SEXP b)
 {
-  SEXP result = PROTECT(allocVector(REALSXP, 1));
-  REAL(result)[0] = asReal(a) - asReal(b);
+  SEXP result = PROTECT(Rf_allocVector(REALSXP, 1));
+  REAL(result)[0] = Rf_asReal(a) - Rf_asReal(b);
   UNPROTECT(1);
   return result;
 }