How to use COCreateGuid and StringFromGuid ,Thanks first !

[neco]

I had written this funtion ,but I don't where are the CoCreateGuid and
StringFromGuid decalred and how to use it ?
Please help me ,thanks first !
//////////////////////////////////////////////////////////////////////////
Function GetUniqueId: String;
Var
Tmp: pWideChar;
Guid: TGuid;
Begin
Result := '';
Tmp := AllocMem( 160 );
Try
CoCreateGuid( Guid );
Guid.D4[ 0 ] := Round( random * 255 );
Guid.D4[ 1 ] := Round( random * 255 );
Guid.D4[ 2 ] := Round( random * 255 );
Guid.D4[ 3 ] := Round( random * 255 );
Guid.D4[ 4 ] := Round( random * 255 );
Guid.D4[ 5 ] := Round( random * 255 );
Guid.D4[ 6 ] := Round( random * 255 );
Guid.D4[ 7 ] := Round( random * 255 );
StringFromGuid2( Guid, Tmp, 40 );
Result := copy( Tmp, 2, length( Tmp ) - 2 );
Finally
FreeMem( Tmp );
End;
End;

[newyj]

uses activex