<html> <head> <title>BOOST_PP_EMPTY</title> <link rel="stylesheet" type="text/css" href="../styles.css"> </head> <body> <div style="margin-left: 0px;"> The <b>BOOST_PP_EMPTY</b> macro is a nullary utility macro that expands to nothing. </div> <h4>Usage</h4> <div class="code"> <b>BOOST_PP_EMPTY</b>() </div> <h4>Remarks</h4> <div> This macro is helps avoid inefficient macro-expansion. It is primarily useful as arguments to <b>BOOST_PP_IF</b> or <b>BOOST_PP_IIF</b>. </div> <h4>Requirements</h4> <div> <b>Header:</b> <a href="../headers/facilities/empty.hpp.html"><boost/preprocessor/facilities/empty.hpp></a> </div> <h4>Sample Code</h4> <div><pre> #include <<a href="../headers/control/if.hpp.html">boost/preprocessor/control/if.hpp</a>> #include <<a href="../headers/facilities/empty.hpp.html">boost/preprocessor/facilities/empty.hpp</a>> #define X() result #define MACRO(c) <a href="if.html">BOOST_PP_IF</a>(c, X, <a href="empty.html">BOOST_PP_EMPTY</a>)() MACRO(0) // expands to nothing MACRO(1) // expands to result </pre></div> </body> </html>
