12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758 |
- <html>
- <head>
- <title>BOOST_PP_IDENTITY_N</title>
- <link rel="stylesheet" type="text/css" href="../styles.css">
- </head>
- <body>
- <div style="margin-left: 0px;">
- The <b>BOOST_PP_IDENTITY_N</b> macro expands to its first argument when invoked.
- </div>
- <h4>Usage</h4>
- <div class="code">
- <b>BOOST_PP_IDENTITY_N</b>(<i>item,n</i>)(n-arguments)
- </div>
- <h4>Arguments</h4>
- <dl>
- <dt>item</dt>
- <dd>
- The result of the expansion.
- </dd>
- <dt>n</dt>
- <dd>
- The number of arguments when invoked.
- </dd>
- </dl>
- <h4>Remarks</h4>
- <div>
- This macro is designed to be used with <b>BOOST_PP_IF</b> and <b>BOOST_PP_IIF</b> when only one of the clauses needs to be invoked.
- </div>
- <h4>See Also</h4>
- <ul>
- <li><a href="if.html">BOOST_PP_IF</a></li>
- <li><a href="iif.html">BOOST_PP_IIF</a></li>
- </ul>
- <h4>Requirements</h4>
- <div>
- <b>Header:</b> <a href="../headers/facilities/identity.html"><boost/preprocessor/facilities/identity.hpp></a>
- </div>
- <h4>Sample Code</h4>
- <div><pre>
- #include <<a href="../headers/control/if.html">boost/preprocessor/control/if.hpp</a>>
- #include <<a href="../headers/facilities/identity.html">boost/preprocessor/facilities/identity.hpp</a>>
- #define MACRO_CAT(y,z) y ## z
- #define MACRO(n) <a href="if.html">BOOST_PP_IF</a>(n, <a href="identity_n.html">BOOST_PP_IDENTITY_N</a>(x,2), MACRO_CAT)(a,b)
- MACRO(0) // expands to ab
- MACRO(1) // expands to x
- </pre></div>
- <hr size="1">
- <div style="margin-left: 0px"><i>© Copyright Edward Diener 2015</i></div>
- <div style="margin-left: 0px;">
- <p><small>Distributed under the Boost Software License, Version 1.0. (See
- accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or
- copy at <a href=
- "http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p>
- </div>
- </body>
- </html>
|