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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>bitmap_ord_to_pos</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Linux Kernel API" /><link rel="up" href="ch03.html#id2962812" title="Bitmap Operations" /><link rel="prev" href="re118.html" title="bitmap_pos_to_ord" /><link rel="next" href="ch03s02.html" title="Command-line Parsing" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>bitmap_ord_to_pos</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re118.html">Prev</a> </td><th width="60%" align="center">Bitmap Operations</th><td width="20%" align="right"> <a accesskey="n" href="ch03s02.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="bitmap_ord_to_pos"><a id="API-bitmap-ord-to-pos"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>bitmap_ord_to_pos —
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">int <b class="fsfunc">bitmap_ord_to_pos </b>(</code></td><td>const unsigned long * <var class="pdparam">buf</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">ord</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">bits</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2966823"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>buf</code></em></span></dt><dd><p>
pointer to bitmap
</p></dd><dt><span class="term"><em class="parameter"><code>ord</code></em></span></dt><dd><p>
ordinal bit position (n-th set bit, n >= 0)
</p></dd><dt><span class="term"><em class="parameter"><code>bits</code></em></span></dt><dd><p>
number of valid bit positions in <em class="parameter"><code>buf</code></em>
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2966890"></a><h2>Description</h2><p>
Map the ordinal offset of bit <em class="parameter"><code>ord</code></em> in <em class="parameter"><code>buf</code></em> to its position in <em class="parameter"><code>buf</code></em>.
Value of <em class="parameter"><code>ord</code></em> should be in range 0 <= <em class="parameter"><code>ord</code></em> < weight(buf), else
results are undefined.
</p><p>
If for example, just bits 4 through 7 are set in <em class="parameter"><code>buf</code></em>, then <em class="parameter"><code>ord</code></em>
values 0 through 3 will get mapped to 4 through 7, respectively,
and all other <em class="parameter"><code>ord</code></em> values return undefined values. When <em class="parameter"><code>ord</code></em> value 3
gets mapped to (returns) <em class="parameter"><code>pos</code></em> value 7 in this example, that means
that the 3rd set bit (starting with 0th) is at position 7 in <em class="parameter"><code>buf</code></em>.
</p><p>
The bit positions 0 through <em class="parameter"><code>bits</code></em> are valid positions in <em class="parameter"><code>buf</code></em>.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re118.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch03.html#id2962812">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch03s02.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>bitmap_pos_to_ord</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Command-line Parsing</td></tr></table></div></body></html>
