t_1_003.cpp

C++的一个好库。。。现在很流行

/*=============================================================================
    Boost.Wave: A Standard compliant C++ preprocessor library
    http://www.boost.org/

    Copyright (c) 2001-2005 Hartmut Kaiser. Distributed under the Boost
    Software License, Version 1.0. (See accompanying file
    LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/

// Tests macro expansion order in conjunction with the need to skip expansion 
// of the same macro as it is currently expanded.

#define CONCAT(a, b) a ## b
#define CONCAT_INDIRECT() CONCAT

//R #line 18 "t_1_003.cpp"
//R CONCAT(1, 2)
CONCAT(CON, CAT)(1, 2)
//R #line 21 "t_1_003.cpp"
//R CONCAT(1, 2)
CONCAT(CON, CAT(1, 2))
//R #line 24 "t_1_003.cpp"
//R 12
CONCAT(CONCAT_, INDIRECT)()(1, 2)
//R #line 27 "t_1_003.cpp"
//R CONCAT(1, 2)
CONCAT(CONCAT_, INDIRECT())(1, 2)
//E t_1_003.cpp(29): error: pasting the following two tokens does not give a valid preprocessing token: "1" and "CONCAT"
CONCAT(1, CONCAT(2, 3))