diff --git a/include/mruby/string.h b/include/mruby/string.h
index b172a3263..faa0d055b 100644
--- a/include/mruby/string.h
+++ b/include/mruby/string.h
@@ -331,9 +331,9 @@ MRB_API const char *mrb_string_cstr(mrb_state *mrb, mrb_value str);
 /* NULL terminated C string from mrb_value; `str` will be updated */
 MRB_API const char *mrb_string_value_cstr(mrb_state *mrb, mrb_value *str);
 /* obsolete: use RSTRING_PTR() */
-MRB_API const char *mrb_string_value_ptr(mrb_state *mrb, mrb_value str);
+#define mrb_string_value_ptr(mrb, str) RSTRING_PTR(str)
 /* obsolete: use RSTRING_LEN() */
-MRB_API mrb_int mrb_string_value_len(mrb_state *mrb, mrb_value str);
+#define mrb_string_value_len(mrb, str) RSTRING_LEN(str)
 /* obsolete: substituted by a macro; shall be removed */
 #define mrb_str_strlen(mrb, s) strlen(RSTR_PTR(s))
 
diff --git a/src/string.c b/src/string.c
index 41d14bd32..111eefb76 100644
--- a/src/string.c
+++ b/src/string.c
@@ -1019,22 +1019,6 @@ mrb_str_equal_m(mrb_state *mrb, mrb_value str1)
 }
 /* ---------------------------------- */
 
-/* obslete: use RSTRING_PTR() */
-MRB_API const char*
-mrb_string_value_ptr(mrb_state *mrb, mrb_value str)
-{
-  str = mrb_obj_as_string(mrb, str);
-  return RSTRING_PTR(str);
-}
-
-/* obslete: use RSTRING_LEN() */
-MRB_API mrb_int
-mrb_string_value_len(mrb_state *mrb, mrb_value ptr)
-{
-  mrb_ensure_string_type(mrb, ptr);
-  return RSTRING_LEN(ptr);
-}
-
 MRB_API mrb_value
 mrb_str_dup(mrb_state *mrb, mrb_value str)
 {