#ifndef BOOST_PREPROCESSOR_EXPR_IF_HPP #define BOOST_PREPROCESSOR_EXPR_IF_HPP /* Copyright (C) 2002 * Housemarque Oy * http://www.housemarque.com * * Permission to copy, use, modify, sell and distribute this software is * granted provided this copyright notice appears in all copies. This * software is provided "as is" without express or implied warranty, and * with no claim as to its suitability for any purpose. * * See http://www.boost.org for most recent version. */ #include /**

Expands to E if C != 0 and to nothing if C == 0.

For example, BOOST_PP_EXPR_IF(1,^) expands to ^.

See

*/ #define BOOST_PP_EXPR_IF(C,E) BOOST_PP_EXPR_IF_BOOL(BOOST_PP_BOOL(C),E) #define BOOST_PP_EXPR_IF_BOOL(C,E) BOOST_PP_EXPR_IF_BOOL_DELAY(C,E) #define BOOST_PP_EXPR_IF_BOOL_DELAY(C,E) BOOST_PP_EXPR_IF_BOOL##C(E) #define BOOST_PP_EXPR_IF_BOOL0(E) #define BOOST_PP_EXPR_IF_BOOL1(E) E #endif