diff --git a/rtl/objpas/sysutils/syspch.inc b/rtl/objpas/sysutils/syspch.inc
index 2ffc5beffc..69b161e997 100644
--- a/rtl/objpas/sysutils/syspch.inc
+++ b/rtl/objpas/sysutils/syspch.inc
@@ -103,10 +103,10 @@ end;
 
 {  StrBufSize returns the amount of memory allocated for pchar Str allocated with StrAlloc  }
 
-function StrBufSize(Str: PChar): SizeUInt;
+function StrBufSize(Str: PChar): Cardinal;
 begin
   if Str <> Nil then
-   result := SizeUInt(pointer(Str - SizeOf(SizeUInt))^)-sizeof(SizeUInt)
+   result := cardinal(pointer(Str - SizeOf(cardinal))^)-sizeof(cardinal)
   else
    result := 0;
 end ;
diff --git a/rtl/objpas/sysutils/syspchh.inc b/rtl/objpas/sysutils/syspchh.inc
index 5fa808410d..82a83a5665 100644
--- a/rtl/objpas/sysutils/syspchh.inc
+++ b/rtl/objpas/sysutils/syspchh.inc
@@ -39,6 +39,6 @@ function StrPas(Str: PChar): string;overload;
 function StrPCopy(Dest: PChar; Source: string): PChar;overload;
 function StrPLCopy(Dest: PChar; Source: string; MaxLen: SizeUInt): PChar;overload;
 function StrAlloc(Size: cardinal): PChar;
-function StrBufSize(Str: PChar): SizeUInt;
+function StrBufSize(Str: PChar): Cardinal;
 procedure StrDispose(Str: PChar);