diff --git a/rtl/inc/astrings.inc b/rtl/inc/astrings.inc
index 092835ebd3..824d6de8a2 100644
--- a/rtl/inc/astrings.inc
+++ b/rtl/inc/astrings.inc
@@ -1180,3 +1180,8 @@ procedure SetCodePage(var s : RawByteString; CodePage : TSystemCodePage; Convert
         PAnsiRec(pointer(s)-AnsiFirstOff)^.CodePage:=CodePage;
       end;
   end;
+
+procedure SetMultiByteConversionCodePage(CodePage: TSystemCodePage);
+  begin
+    DefaultSystemCodePage:=CodePage;
+  end;
\ No newline at end of file
diff --git a/rtl/inc/systemh.inc b/rtl/inc/systemh.inc
index 17b8a74d3b..0b12495348 100644
--- a/rtl/inc/systemh.inc
+++ b/rtl/inc/systemh.inc
@@ -881,9 +881,10 @@ Function  StringOfChar(c : char;l : SizeInt) : AnsiString;
 function  upcase(const s : ansistring) : ansistring;
 function  lowercase(const s : ansistring) : ansistring;
 
-function StringCodePage(const S : RawByteString): Word; overload;
+function StringCodePage(const S : RawByteString): TSystemCodePage; overload;
 function StringElementSize(const S : RawByteString): Word; overload;
 function StringRefCount(const S : RawByteString): SizeInt; overload;
+procedure SetMultiByteConversionCodePage(CodePage: TSystemCodePage);
 {$endif FPC_HAS_FEATURE_ANSISTRINGS}
 
 
diff --git a/rtl/inc/ustringh.inc b/rtl/inc/ustringh.inc
index 7a3c9e337a..2e3dce5bb6 100644
--- a/rtl/inc/ustringh.inc
+++ b/rtl/inc/ustringh.inc
@@ -130,4 +130,4 @@ Procedure SetUnicodeStringManager (Const New : TUnicodeStringManager; Var Old: T
 
 function StringElementSize(const S : UnicodeString): Word; overload;
 function StringRefCount(const S : UnicodeString): SizeInt; overload;
-function StringCodePage(const S : UnicodeString): Word; overload;
+function StringCodePage(const S : UnicodeString): TSystemCodePage; overload;