boost_core/doc/ignore_unused.qbk

[/
  Copyright 2014 Adam Wulkiewicz

  Distributed under the Boost Software License, Version 1.0.

  See accompanying file LICENSE_1_0.txt
  or copy at http://boost.org/LICENSE_1_0.txt
]

[section:ignore_unused ignore_unused]

[section Authors]

* Adam Wulkiewicz

[endsect]

[section Header <boost/core/ignore_unused.hpp>]

The header `<boost/core/ignore_unused.hpp>` defines the function template
`boost::ignore_unused()`. It may be used to suppress the "unused variable" or
"unused local typedefs" compiler warnings when the variable or typedef
can't be removed or commented out, e.g. when some blocks of the code are
conditionally activated. C++11 variadic templates are used if they're supported,
otherwise they're emulated with overloads.

[section Usage]

``
boost::ignore_unused(v1, v2, v3);
boost::ignore_unused<T1, T2, T3>();
``

[endsect]

[section Example]

``
int fun( int foo, int bar )
{
    boost::ignore_unused(bar);
#ifdef ENABLE_DEBUG_OUTPUT
    if ( foo < bar )
        std::cerr << "warning! foo < bar";
#endif
    return foo + 2;
}
``

[endsect]

[endsect]

[section Acknowledgments]

`boost::ignore_unused()` was contributed by Adam Wulkiewicz.

[endsect]

[endsect]