# Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world.

### boost/vmd/assert_is_empty.hpp


//  (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

#if !defined(BOOST_VMD_ASSERT_IS_EMPTY_HPP)
#define BOOST_VMD_ASSERT_IS_EMPTY_HPP

#include <boost/vmd/detail/setup.hpp>

#if BOOST_VMD_ASSERT_DATA

#include <boost/vmd/assert.hpp>
#include <boost/vmd/is_empty.hpp>

#endif

/*

The succeeding comments in this file are in doxygen format.

*/

/** \file
*/

/** \def BOOST_VMD_ASSERT_IS_EMPTY(...)

\brief Asserts that the input is empty.

The macro checks to see if the input is empty or not.
If it is not empty, it forces a compiler error.

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 and not variadic data.

The macro normally checks for emptiness only in
debug mode. However an end-user can force the macro
to check or not check by defining the macro
BOOST_VMD_ASSERT_DATA to 1 or 0 respectively.

.... = variadic input, for VC++8 this must be a single parameter.

returns = Normally the macro returns nothing.

If the input is empty, nothing is output.

For VC++, because there is no sure way of forcing
a compiler error from within a macro without producing
output, if the input is not empty the
macro forces a compiler error by outputting invalid C++.

For all other compilers a compiler error is forced
without producing output if the input is not empty.

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

#if !BOOST_VMD_ASSERT_DATA

#define BOOST_VMD_ASSERT_IS_EMPTY(input)

#else

#define BOOST_VMD_ASSERT_IS_EMPTY(input) \
BOOST_VMD_ASSERT \
( \
BOOST_VMD_IS_EMPTY(input), \
BOOST_VMD_IS_EMPTY_ASSERT_ERROR \
) \
/**/

#endif // !BOOST_VMD_ASSERT_DATA

#else

#if !BOOST_VMD_ASSERT_DATA

#define BOOST_VMD_ASSERT_IS_EMPTY(...)

#else

#define BOOST_VMD_ASSERT_IS_EMPTY(...) \
BOOST_VMD_ASSERT \
( \
BOOST_VMD_IS_EMPTY(__VA_ARGS__), \
BOOST_VMD_IS_EMPTY_ASSERT_ERROR \
) \
/**/

#endif // !BOOST_VMD_ASSERT_DATA

#endif /* BOOST_VMD_MSVC_V8 */