diff --git a/lcl/include/winapi.inc b/lcl/include/winapi.inc
index 4643928821..a43ed379a9 100644
--- a/lcl/include/winapi.inc
+++ b/lcl/include/winapi.inc
@@ -1106,6 +1106,24 @@ begin
   Result := UpperCaseChars[c];
 end;
 
+{------------------------------------------------------------------------------
+  Function: CharUpperBuff
+  Params: pStr:
+          Len:
+  Returns:
+
+ ------------------------------------------------------------------------------}
+function CharUpperBuff(pStr: PChar; Len: Integer): Integer;
+begin
+  Result := len;
+  while len > 0 do
+  begin
+    pStr^ := UpperCaseChars[pStr^];
+    inc(pStr);
+    dec(len);
+  end;
+end;
+
 {------------------------------------------------------------------------------
   Function: CopyRect  pbd
   Params:
diff --git a/lcl/include/winapih.inc b/lcl/include/winapih.inc
index d2161efe3d..7be05866a1 100644
--- a/lcl/include/winapih.inc
+++ b/lcl/include/winapih.inc
@@ -298,6 +298,7 @@ function AdjustWindowRectEx(Var Rect: TRect; Style1: Word; MenuExist : Boolean;
 function CharLower(c: char): char; inline;
 function CharLowerBuff(pStr : PChar; Len : Integer): Integer;
 function CharUpper(c: char): char; inline;
+function CharUpperBuff(pStr : PChar; Len : Integer): Integer;
 function CopyRect(var DestRect: TRect; const SrcRect: TRect): Boolean;
 function CreateEllipticRgnIndirect(const ARect: TRect): HRGN;
 function CreateFont(Height, Width, Escapement, Orientation, Weight: Integer;