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- // (C) Copyright Edward Diener 2011-2015
- // Use, modification and distribution are subject to 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).
- #if !defined(BOOST_VMD_IS_EMPTY_HPP)
- #define BOOST_VMD_IS_EMPTY_HPP
- #include <boost/vmd/detail/setup.hpp>
- #if BOOST_PP_VARIADICS
- #include <boost/preprocessor/punctuation/is_begin_parens.hpp>
- #include <boost/vmd/detail/is_empty.hpp>
- /*
- The succeeding comments in this file are in doxygen format.
- */
- /** \file
- */
- /** \def BOOST_VMD_IS_EMPTY(...)
- \brief Tests whether its input is empty or not.
- The macro checks to see if the input is empty or not.
- It returns 1 if the input is empty, else returns 0.
-
- The macro is a variadic macro taking any input.
- For the VC++8 compiler (VS2005) the macro takes a single parameter of input to check.
-
- The macro is not perfect, and can not be so. The problem
- area is if the input to be checked is a function-like
- macro name, in which case either a compiler error can result
- or a false result can occur.
-
- This macro is a replacement, using variadic macro support,
- for the undocumented macro BOOST_PP_IS_EMPTY in the Boost
- PP library. The code is taken from a posting by Paul Mensonides
- of a variadic version for BOOST_PP_IS_EMPTY, and changed
- in order to also support VC++.
-
- .... = variadic input, for VC++8 this must be a single parameter
- returns = 1 if the input is empty, 0 if it is not
-
- It is recommended to append BOOST_PP_EMPTY() to whatever input
- is being tested in order to avoid possible warning messages
- from some compilers about no parameters being passed to the macro
- when the input is truly empty.
-
- */
- #if BOOST_VMD_MSVC_V8
- #define BOOST_VMD_IS_EMPTY(sequence) \
- BOOST_VMD_DETAIL_IS_EMPTY_IIF \
- ( \
- BOOST_PP_IS_BEGIN_PARENS \
- ( \
- sequence \
- ) \
- ) \
- ( \
- BOOST_VMD_DETAIL_IS_EMPTY_GEN_ZERO, \
- BOOST_VMD_DETAIL_IS_EMPTY_PROCESS \
- ) \
- (sequence) \
- /**/
- #else
- #define BOOST_VMD_IS_EMPTY(...) \
- BOOST_VMD_DETAIL_IS_EMPTY_IIF \
- ( \
- BOOST_PP_IS_BEGIN_PARENS \
- ( \
- __VA_ARGS__ \
- ) \
- ) \
- ( \
- BOOST_VMD_DETAIL_IS_EMPTY_GEN_ZERO, \
- BOOST_VMD_DETAIL_IS_EMPTY_PROCESS \
- ) \
- (__VA_ARGS__) \
- /**/
- #endif /* BOOST_VMD_MSVC_V8 */
- #endif /* BOOST_PP_VARIADICS */
- #endif /* BOOST_VMD_IS_EMPTY_HPP */
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