diff --git a/rtl/objpas/sysutils/sysuni.inc b/rtl/objpas/sysutils/sysuni.inc
index b5425f2bee..a028cca159 100644
--- a/rtl/objpas/sysutils/sysuni.inc
+++ b/rtl/objpas/sysutils/sysuni.inc
@@ -195,8 +195,8 @@ function StrMove(dest,source : PWideChar;l : SizeInt) : PWideChar; overload;
  end;
 
 
-function StrPLCopy(Dest: PWideChar; const Source: UnicodeString; MaxLen: SizeInt): PWideChar; overload;
-var Len: SizeInt;
+function StrPLCopy(Dest: PWideChar; const Source: UnicodeString; MaxLen: SizeUInt): PWideChar; overload;
+var Len: SizeUInt;
 begin
   Len := length(Source);
   if Len > MaxLen then
diff --git a/rtl/objpas/sysutils/sysunih.inc b/rtl/objpas/sysutils/sysunih.inc
index 68d444b192..22f4bbfd73 100644
--- a/rtl/objpas/sysutils/sysunih.inc
+++ b/rtl/objpas/sysutils/sysunih.inc
@@ -36,7 +36,7 @@ Procedure UnicodeFmtStr(Var Res: UnicodeString; Const Fmt : UnicodeString; Const
 Procedure UnicodeFmtStr(Var Res: UnicodeString; Const Fmt : UnicodeString; Const args: Array of const; Const FormatSettings: TFormatSettings);
 
 function StrMove(dest,source : PWideChar;l : SizeInt) : PWideChar; overload;
-function StrPLCopy(Dest: PWideChar; const Source: UnicodeString; MaxLen: SizeInt): PWideChar; overload;
+function StrPLCopy(Dest: PWideChar; const Source: UnicodeString; MaxLen: SizeUInt): PWideChar; overload;
 function StrPCopy(Dest: PWideChar; const Source: UnicodeString): PWideChar; overload;
 function StrScan(P: PWideChar; C: WideChar): PWideChar; overload;
 function strnew(p : PWideChar) : PWideChar; overload;