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91 lines
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91 lines
3.0 KiB
HTML
<html>
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<head>
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<title>BOOST_PP_RELATIVE_ITERATION</title>
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<link rel="stylesheet" type="text/css" href="../styles.css">
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</head>
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<body>
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<div style="margin-left: 0px;">
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The <b>BOOST_PP_RELATIVE_ITERATION</b> macro expands to the iteration value of a <i>file-iteration</i> depth relative to the current depth.
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</div>
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<h4>Usage</h4>
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<div class="code">
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<b>BOOST_PP_RELATIVE_ITERATION</b>(<i>i</i>)
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</div>
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<h4>Arguments</h4>
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<dl>
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<dt>i</dt>
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<dd>
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The relative depth of the frame whose iteration value is to be retreived.
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Valid values range from <i>0</i> to <b>BOOST_PP_ITERATION_DEPTH</b>() - <i>1</i>.
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</dd>
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</dl>
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<h4>Remarks</h4>
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<div>
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This macro is only valid when a <i>file-iteration</i> is in progress.
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</div>
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<div>
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The argument <i>i</i> is interpreted as the number of frames <i>outward</i> from the current frame.
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Therefore, <b>BOOST_PP_RELATIVE_ITERATION</b>(<i>0</i>) is equivalent to <b>BOOST_PP_ITERATION</b>().
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</div>
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<h4>Requirements</h4>
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<div>
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<b>Header:</b> <a href="../headers/iteration/iterate.html"><boost/preprocessor/iteration/iterate.hpp></a>
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</div>
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<h4>Sample Code</h4>
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<div><pre>
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// file.h
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#if !<a href="is_iterating.html">BOOST_PP_IS_ITERATING</a>
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#ifndef FILE_H_
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#define FILE_H_
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#include <<a href="../headers/iteration/iterate.html">boost/preprocessor/iteration/iterate.hpp</a>>
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1st iteration:
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#define <a href="iteration_params_x.html">BOOST_PP_ITERATION_PARAMS_1</a> (4, (0, 3, "file.h", 0x0001))
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#include <a href="iterate.html">BOOST_PP_ITERATE</a>()
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2nd iteration:
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#define <a href="iteration_params_x.html">BOOST_PP_ITERATION_PARAMS_1</a> (4, (1, 10, "file.h", 0x0002))
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#include <a href="iterate.html">BOOST_PP_ITERATE</a>()
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#endif
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#elif <a href="iteration_depth.html">BOOST_PP_ITERATION_DEPTH</a>() == 1 \
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&& <a href="iteration_flags.html">BOOST_PP_ITERATION_FLAGS</a>() == 0x0001 \
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/**/
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--
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#define <a href="iteration_params_x.html">BOOST_PP_ITERATION_PARAMS_2</a> (3, (1, 10, "file.h"))
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#include <a href="iterate.html">BOOST_PP_ITERATE</a>()
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#elif <a href="iteration_depth.html">BOOST_PP_ITERATION_DEPTH</a>() == 1 \
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&& <a href="iteration_flags.html">BOOST_PP_ITERATION_FLAGS</a>() == 0x0002 \
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/**/
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--
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#define <a href="iteration_params_x.html">BOOST_PP_ITERATION_PARAMS_2</a> \
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(3, (1, <a href="iteration.html">BOOST_PP_ITERATION</a>(), "file.h")) \
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/**/
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#include <a href="iterate.html">BOOST_PP_ITERATE</a>()
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#elif <a href="iteration_depth.html">BOOST_PP_ITERATION_DEPTH</a>() == 2 \
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&& <a href="frame_flags.html">BOOST_PP_FRAME_FLAGS</a>(1) == 0x0001 \
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/**/
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--
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#define <a href="iteration_params_x.html">BOOST_PP_ITERATION_PARAMS_3</a> \
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(3, (1, <a href="iteration.html">BOOST_PP_ITERATION</a>(), "file.h")) \
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/**/
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#include <a href="iterate.html">BOOST_PP_ITERATE</a>()
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#else // used by both
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previous: <a href="relative_iteration.html">BOOST_PP_RELATIVE_ITERATION</a>(1)
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current: <a href="iteration.html">BOOST_PP_ITERATION</a>()
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#endif
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</pre></div>
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</body>
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</html>
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