www.pudn.com > Loki.rar > static_check.h

//////////////////////////////////////////////////////////////////////////////// 
// The Loki Library 
// Copyright (c) 2001 by Andrei Alexandrescu 
// This code accompanies the book: 
// Alexandrescu, Andrei. "Modern C++ Design: Generic Programming and Design  
//     Patterns Applied". Copyright (c) 2001. Addison-Wesley. 
// Permission to use, copy, modify, distribute and sell this software for any  
//     purpose is hereby granted without fee, provided that the above copyright  
//     notice appear in all copies and that both that copyright notice and this  
//     permission notice appear in supporting documentation. 
// The author or Addison-Welsey Longman make no representations about the  
//     suitability of this software for any purpose. It is provided "as is"  
//     without express or implied warranty. 
//////////////////////////////////////////////////////////////////////////////// 
 
// Last update: June 20, 2001 
 
#ifndef STATIC_CHECK_INC_ 
#define STATIC_CHECK_INC_ 
 
namespace Loki 
{ 
//////////////////////////////////////////////////////////////////////////////// 
// Helper structure for the STATIC_CHECK macro 
//////////////////////////////////////////////////////////////////////////////// 
 
    template 
    struct CompileTimeError; 
 
    template<>  
    struct CompileTimeError  
    { 
        typedef void type; 
    }; 
} 
 
//////////////////////////////////////////////////////////////////////////////// 
// macro STATIC_CHECK 
// Invocation: STATIC_CHECK(expr, id) 
// where: 
// expr is a compile-time integral or pointer expression 
// id is a C++ identifier that does not need to be defined 
// If expr is zero, id will appear in a compile-time error message. 
//////////////////////////////////////////////////////////////////////////////// 
 
#define STATIC_CHECK(expr, msg) \ 
typedef char ERROR_##msg[1][(expr)] 
 
//////////////////////////////////////////////////////////////////////////////// 
// Change log: 
// March 20, 2001: add extra parens to STATIC_CHECK - it looked like a fun  
//     definition 
// June 20, 2001: ported by Nick Thurn to gcc 2.95.3. Kudos, Nick!!! 
// July 09, 2002: improved for favor of VC diagnostic and usage  
//////////////////////////////////////////////////////////////////////////////// 
 
#endif // STATIC_CHECK_INC_