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- <title>BOOST_PP_LPAREN_IF</title>
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- The <b>BOOST_PP_LPAREN_IF</b> macro conditionally expands to a left parenthesis.
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- <h4>Usage</h4>
- <div class="code">
- <b>BOOST_PP_LPAREN_IF</b>(<i>cond</i>)
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- <h4>Arguments</h4>
- <dl>
- <dt>cond</dt>
- <dd>
- The condition that determines if a the macro expands to a left parenthesis or nothing.
- Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>.
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- <h4>Remarks</h4>
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- If <i>cond</i> expands to <i>0</i>, this macro expands to nothing.
- Otherwise, it expands to a left parenthesis.
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- The preprocessor interprets parentheses as delimiters in macro invocations.
- Because of this, parentheses require special handling.
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- <h4>See Also</h4>
- <ul>
- <li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li>
- <li><a href="rparen_if.html">BOOST_PP_RPAREN_IF</a></li>
- </ul>
- <h4>Requirements</h4>
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- <b>Header:</b> <a href="../headers/punctuation/paren_if.html"><boost/preprocessor/punctuation/paren_if.hpp></a>
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- <h4>Sample Code</h4>
- <div><pre>
- #include <<a href="../headers/punctuation/paren_if.html">boost/preprocessor/punctuation/paren_if.hpp</a>>
- #define MACRO(c, x) <a href="lparen_if.html">BOOST_PP_LPAREN_IF</a>(c) x <a href="rparen_if.html">BOOST_PP_RPAREN_IF</a>(c)
- MACRO(0, text) // expands to text
- MACRO(1, text) // expands to (text)
- </pre></div>
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- <i>© Copyright <a href="http://www.housemarque.com" target="_top">Housemarque Oy</a> 2002</i>
- </br><i>© Copyright Paul Mensonides 2002</i>
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- <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>
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