1<html> 2 <head> 3 <meta content="text/html; charset=windows-1252" http-equiv="content-type"> 4 <title>BOOST_PP_IS_BEGIN_PARENS</title> 5 <link rel="stylesheet" type="text/css" href="../styles.css"> 6 </head> 7 <body> 8 <div style="margin-left: 0px;"> The <b>BOOST_PP_IS_BEGIN_PAREN</b>S 9 determines whether the input starts with a set of parenthesis.</div> 10 <h4>Usage</h4> 11 <div class="code"> <b>BOOST_PP_IS_BEGIN_PARENS</b>(...) <a href="../topics/variadic_macros.html#VNotation" 12 target="_self"><sup>(v)</sup></a></div> 13 <h4>Arguments</h4> 14 <h4> ... <span style="font-weight: normal;"> 15 The input as variadic data.</span></h4> 16 <h4>Remarks</h4> 17 <div> If the input input begins with a parenthesis, with any data within 18 that parenthesis, the macro returns 1, otherwise it returns 0. Data may 19 follow the beginning parenthesis and the macro still will return 1.<br> 20 <br> 21 For Visual Studio 2005 ( VC8 ) the input data must be a single parameter 22 else a compilation error will occur.</div> 23 <h4>See Also</h4> 24 <ul> 25 <li><a href="remove_parens.html">BOOST_PP_REMOVE_PARENS</a></li> 26 </ul> 27 <h4>Requirements</h4> 28 <div> <b>Header:</b> <a href="../headers/punctuation/is_begin_parens.html"><boost/preprocessor/punctuation/is_begin_parens.hpp></a> 29 </div> 30 <h4>Sample Code</h4> 31 <div> 32 <pre>#include <<a href="../headers/punctuation/is_begin_parens.html">boost/preprocessor/punctuation/is_begin_parens.hpp</a>> 33 34#define VARDATA more_data , more_params<br>#define VARDATAP ( data ) more_data , more_params<br>#define DATA data<br>#define DATAP ( data ) more_data<br> 35BOOST_PP_IS_BEGIN_PARENS(VARDATA) // expands to 0, compiler error with VC8 36BOOST_PP_IS_BEGIN_PARENS(VARDATAP) // expands to 1, compiler error with VC8<br><br>BOOST_PP_IS_BEGIN_PARENS(DATA) // expands to 0 37BOOST_PP_IS_BEGIN_PARENS(DATAP) // expands to 1<br><br>BOOST_PP_IS_BEGIN_PARENS() // expands to 0<br> 38</pre></div> 39 <hr size="1"> 40 <div style="margin-left: 0px;"> <i>� Copyright Edward Diener 2014</i> </div> 41 <div style="margin-left: 0px;"> 42 <p><small>Distributed under the Boost Software License, Version 1.0. (See 43 accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> 44 or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">www.boost.org/LICENSE_1_0.txt</a>)</small></p> 45 </div> 46 </body> 47</html> 48