ceph/src/boost/libs/core/doc/ignore_unused.qbk

   1 [/
   2   Copyright 2014 Adam Wulkiewicz
   3
   4   Distributed under the Boost Software License, Version 1.0.
   5
   6   See accompanying file LICENSE_1_0.txt
   7   or copy at http://boost.org/LICENSE_1_0.txt
   8 ]
   9
  10 [section:ignore_unused ignore_unused]
  11
  12 [simplesect Authors]
  13
  14 * Adam Wulkiewicz
  15
  16 [endsimplesect]
  17
  18 [section Header <boost/core/ignore_unused.hpp>]
  19
  20 The header `<boost/core/ignore_unused.hpp>` defines the function template
  21 `boost::ignore_unused()`. It may be used to suppress the "unused variable" or
  22 "unused local typedefs" compiler warnings when the variable or typedef
  23 can't be removed or commented out, e.g. when some blocks of the code are
  24 conditionally activated. C++11 variadic templates are used if they're supported,
  25 otherwise they're emulated with overloads.
  26
  27 [section Usage]
  28
  29 ``
  30 boost::ignore_unused(v1, v2, v3);
  31 boost::ignore_unused<T1, T2, T3>();
  32 ``
  33
  34 [endsect]
  35
  36 [section Example]
  37
  38 ``
  39 int fun( int foo, int bar )
  40 {
  41     boost::ignore_unused(bar);
  42 #ifdef ENABLE_DEBUG_OUTPUT
  43     if ( foo < bar )
  44         std::cerr << "warning! foo < bar";
  45 #endif
  46     return foo + 2;
  47 }
  48 ``
  49
  50 [endsect]
  51
  52 [endsect]
  53
  54 [section Acknowledgments]
  55
  56 `boost::ignore_unused()` was contributed by Adam Wulkiewicz.
  57
  58 [endsect]
  59
  60 [endsect]