path: root/static/freebsd/man9/bitset.9 3.html

<table class="head">
  <tr>
    <td class="head-ltitle">BITSET(9)</td>
    <td class="head-vol">Kernel Developer's Manual</td>
    <td class="head-rtitle">BITSET(9)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">bitset(9)</code> &#x2014;
    <code class="Nm">BITSET_DEFINE</code>,
    <code class="Nm">BITSET_T_INITIALIZER</code>,
    <code class="Nm">BITSET_FSET</code>, <code class="Nm">BIT_CLR</code>,
    <code class="Nm">BIT_COPY</code>, <code class="Nm">BIT_ISSET</code>,
    <code class="Nm">BIT_SET</code>, <code class="Nm">BIT_ZERO</code>,
    <code class="Nm">BIT_FILL</code>, <code class="Nm">BIT_SETOF</code>,
    <code class="Nm">BIT_EMPTY</code>, <code class="Nm">BIT_ISFULLSET</code>,
    <code class="Nm">BIT_FFS</code>, <code class="Nm">BIT_FFS_AT</code>,
    <code class="Nm">BIT_FLS</code>, <code class="Nm">BIT_FOREACH_ISSET</code>,
    <code class="Nm">BIT_FOREACH_ISCLR</code>,
    <code class="Nm">BIT_COUNT</code>, <code class="Nm">BIT_SUBSET</code>,
    <code class="Nm">BIT_OVERLAP</code>, <code class="Nm">BIT_CMP</code>,
    <code class="Nm">BIT_OR</code>, <code class="Nm">BIT_OR2</code>,
    <code class="Nm">BIT_ORNOT</code>, <code class="Nm">BIT_ORNOT2</code>,
    <code class="Nm">BIT_AND</code>, <code class="Nm">BIT_AND2</code>,
    <code class="Nm">BIT_ANDNOT</code>, <code class="Nm">BIT_ANDNOT2</code>,
    <code class="Nm">BIT_XOR</code>, <code class="Nm">BIT_XOR2</code>,
    <code class="Nm">BIT_CLR_ATOMIC</code>,
    <code class="Nm">BIT_SET_ATOMIC</code>,
    <code class="Nm">BIT_SET_ATOMIC_ACQ</code>,
    <code class="Nm">BIT_TEST_SET_ATOMIC</code>,
    <code class="Nm">BIT_TEST_CLR_ATOMIC</code>,
    <code class="Nm">BIT_AND_ATOMIC</code>,
    <code class="Nm">BIT_OR_ATOMIC</code>,
    <code class="Nm">BIT_COPY_STORE_REL</code> &#x2014; <span class="Nd">bitset
    manipulation macros</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
    &lt;<a class="In">sys/_bitset.h</a>&gt;</code>
  <br/>
  <code class="In">#include &lt;<a class="In">sys/bitset.h</a>&gt;</code></p>
<p class="Pp"><code class="Fn">BITSET_DEFINE</code>(<var class="Fa" style="white-space: nowrap;">STRUCTNAME</var>,
    <var class="Fa" style="white-space: nowrap;">const SETSIZE</var>);</p>
<p class="Pp"><code class="Fn">BITSET_T_INITIALIZER</code>(<var class="Fa" style="white-space: nowrap;">ARRAY_CONTENTS</var>);</p>
<p class="Pp"><code class="Fn">BITSET_FSET</code>(<var class="Fa" style="white-space: nowrap;">N_WORDS</var>);</p>
<p class="Pp"><code class="Fn">BIT_CLR</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_COPY</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *from</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *to</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_ISSET</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_SET</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_ZERO</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_FILL</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_SETOF</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_EMPTY</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_ISFULLSET</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><var class="Ft">long</var>
  <br/>
  <code class="Fn">BIT_FFS</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><var class="Ft">long</var>
  <br/>
  <code class="Fn">BIT_FFS_AT</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>, <var class="Fa" style="white-space: nowrap;">long
    start</var>);</p>
<p class="Pp"><var class="Ft">long</var>
  <br/>
  <code class="Fn">BIT_FLS</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_FOREACH_ISSET</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">size_t bit</var>, <var class="Fa">const
    struct STRUCTNAME *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_FOREACH_ISCLR</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">size_t bit</var>, <var class="Fa">const
    struct STRUCTNAME *bitset</var>);</p>
<p class="Pp"><var class="Ft">long</var>
  <br/>
  <code class="Fn">BIT_COUNT</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *bitset</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_SUBSET</code>(<var class="Fa">const SETSIZE</var>,
    <var class="Fa">struct STRUCTNAME *haystack</var>, <var class="Fa">struct
    STRUCTNAME *needle</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_OVERLAP</code>(<var class="Fa">const SETSIZE</var>,
    <var class="Fa">struct STRUCTNAME *bitset1</var>, <var class="Fa">struct
    STRUCTNAME *bitset2</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_CMP</code>(<var class="Fa">const SETSIZE</var>,
    <var class="Fa">struct STRUCTNAME *bitset1</var>, <var class="Fa">struct
    STRUCTNAME *bitset2</var>);</p>
<p class="Pp"><code class="Fn">BIT_OR</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *dst</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_OR2</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src1</var>, <var class="Fa">struct
    STRUCTNAME *src2</var>);</p>
<p class="Pp"><code class="Fn">BIT_ORNOT</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *dst</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_ORNOT2</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src1</var>, <var class="Fa">struct
    STRUCTNAME *src2</var>);</p>
<p class="Pp"><code class="Fn">BIT_AND</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *dst</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_AND2</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src1</var>, <var class="Fa">struct
    STRUCTNAME *src2</var>);</p>
<p class="Pp"><code class="Fn">BIT_ANDNOT</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *dst</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_ANDNOT2</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src1</var>, <var class="Fa">struct
    STRUCTNAME *src2</var>);</p>
<p class="Pp"><code class="Fn">BIT_XOR</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *dst</var>, <var class="Fa" style="white-space: nowrap;">struct
    STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_XOR2</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src1</var>, <var class="Fa">struct
    STRUCTNAME *src2</var>);</p>
<p class="Pp"><code class="Fn">BIT_CLR_ATOMIC</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_SET_ATOMIC</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_SET_ATOMIC_ACQ</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_TEST_SET_ATOMIC</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><var class="Ft">bool</var>
  <br/>
  <code class="Fn">BIT_TEST_CLR_ATOMIC</code>(<var class="Fa" style="white-space: nowrap;">const
    SETSIZE</var>, <var class="Fa" style="white-space: nowrap;">size_t
    bit</var>, <var class="Fa" style="white-space: nowrap;">struct STRUCTNAME
    *bitset</var>);</p>
<p class="Pp"><code class="Fn">BIT_AND_ATOMIC</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_OR_ATOMIC</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *dst</var>,
    <var class="Fa">struct STRUCTNAME *src</var>);</p>
<p class="Pp"><code class="Fn">BIT_COPY_STORE_REL</code>(<var class="Fa">const
    SETSIZE</var>, <var class="Fa">struct STRUCTNAME *from</var>,
    <var class="Fa">struct STRUCTNAME *to</var>);</p>
<p class="Pp"><code class="Fd">#define _WANT_FREEBSD_BITSET</code></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">bitset(9)</code> family of macros provide a
    flexible and efficient bitset implementation if the maximum size of the set
    is known at compilation. Throughout this manual page, the name
    <var class="Fa">SETSIZE</var> refers to the size of the bitset in bits.
    Individual bits in bitsets are referenced with indices zero through
    <var class="Fa">SETSIZE - 1</var>. One example use of
    <code class="In">&lt;<a class="In">sys/bitset.h</a>&gt;</code> is
    <code class="In">&lt;<a class="In">sys/cpuset.h</a>&gt;</code>.</p>
<p class="Pp">These macros are meant to be used in the kernel and are visible if
    <code class="Dv">_KERNEL is defined when</code>
    <code class="In">&lt;<a class="In">sys/_bitset.h</a>&gt;</code> or
    <code class="In">&lt;<a class="In">sys/bitset.h</a>&gt;</code> are included
    in a program. Userland programs must define
    <code class="Dv">_WANT_FREEBSD_BITSET</code> before including these files to
    make the macros visible.</p>
<p class="Pp" id="BITSET_DEFINE">The
    <a class="permalink" href="#BITSET_DEFINE"><code class="Fn">BITSET_DEFINE</code></a>()
    macro defines a bitset struct <var class="Fa">STRUCTNAME</var> with room to
    represent <var class="Fa">SETSIZE</var> bits.</p>
<p class="Pp" id="BITSET_T_INITIALIZER">The
    <a class="permalink" href="#BITSET_T_INITIALIZER"><code class="Fn">BITSET_T_INITIALIZER</code></a>()
    macro allows one to initialize a bitset struct with a compile time literal
    value.</p>
<p class="Pp" id="BITSET_FSET">The
    <a class="permalink" href="#BITSET_FSET"><code class="Fn">BITSET_FSET</code></a>()
    macro generates a compile time literal, usable by
    <code class="Fn">BITSET_T_INITIALIZER</code>(), representing a full bitset
    (all bits set). For examples of
    <code class="Fn">BITSET_T_INITIALIZER</code>() and
    <code class="Fn">BITSET_FSET</code>() usage, see the
    <a class="Sx" href="#BITSET_T_INITIALIZER_EXAMPLE">BITSET_T_INITIALIZER
    EXAMPLE</a> section. The <var class="Fa">N_WORDS</var> parameter to
    <code class="Fn">BITSET_FSET</code>() should be:</p>
<div class="Bd Pp Bd-indent Li">
<pre>__bitset_words(SETSIZE)</pre>
</div>
<p class="Pp" id="BIT_CLR">The
    <a class="permalink" href="#BIT_CLR"><code class="Fn">BIT_CLR</code></a>()
    macro clears bit <var class="Fa">bit</var> in the bitset pointed to by
    <var class="Fa">bitset</var>. The
    <a class="permalink" href="#BIT_CLR_ATOMIC"><code class="Fn" id="BIT_CLR_ATOMIC">BIT_CLR_ATOMIC</code></a>()
    macro is identical, but the bit is cleared atomically. The
    <a class="permalink" href="#BIT_TEST_CLR_ATOMIC"><code class="Fn" id="BIT_TEST_CLR_ATOMIC">BIT_TEST_CLR_ATOMIC</code></a>()
    macro atomically clears the bit and returns whether it was set.</p>
<p class="Pp" id="BIT_COPY">The
    <a class="permalink" href="#BIT_COPY"><code class="Fn">BIT_COPY</code></a>()
    macro copies the contents of the bitset <var class="Fa">from</var> to the
    bitset <var class="Fa">to</var>.
    <a class="permalink" href="#BIT_COPY_STORE_REL"><code class="Fn" id="BIT_COPY_STORE_REL">BIT_COPY_STORE_REL</code></a>()
    is similar, but copies component machine words from
    <var class="Fa">from</var> and writes them to <var class="Fa">to</var> with
    atomic store with release semantics. (That is, if <var class="Fa">to</var>
    is composed of multiple machine words,
    <code class="Fn">BIT_COPY_STORE_REL</code>() performs multiple individually
    atomic operations.)</p>
<p class="Pp" id="BIT_ISSET">The
    <a class="permalink" href="#BIT_ISSET"><code class="Fn">BIT_ISSET</code></a>()
    macro returns <code class="Dv">true</code> if the bit
    <var class="Fa">bit</var> in the bitset pointed to by
    <var class="Fa">bitset</var> is set.</p>
<p class="Pp" id="BIT_SET">The
    <a class="permalink" href="#BIT_SET"><code class="Fn">BIT_SET</code></a>()
    macro sets bit <var class="Fa">bit</var> in the bitset pointed to by
    <var class="Fa">bitset</var>. The
    <a class="permalink" href="#BIT_SET_ATOMIC"><code class="Fn" id="BIT_SET_ATOMIC">BIT_SET_ATOMIC</code></a>()
    macro is identical, but the bit is set atomically. The
    <a class="permalink" href="#BIT_SET_ATOMIC_ACQ"><code class="Fn" id="BIT_SET_ATOMIC_ACQ">BIT_SET_ATOMIC_ACQ</code></a>()
    macro sets the bit with acquire semantics. The
    <a class="permalink" href="#BIT_TEST_SET_ATOMIC"><code class="Fn" id="BIT_TEST_SET_ATOMIC">BIT_TEST_SET_ATOMIC</code></a>()
    macro atomically sets the bit and returns whether it was set.</p>
<p class="Pp" id="BIT_ZERO">The
    <a class="permalink" href="#BIT_ZERO"><code class="Fn">BIT_ZERO</code></a>()
    macro clears all bits in <var class="Fa">bitset</var>.</p>
<p class="Pp" id="BIT_FILL">The
    <a class="permalink" href="#BIT_FILL"><code class="Fn">BIT_FILL</code></a>()
    macro sets all bits in <var class="Fa">bitset</var>.</p>
<p class="Pp" id="BIT_SETOF">The
    <a class="permalink" href="#BIT_SETOF"><code class="Fn">BIT_SETOF</code></a>()
    macro clears all bits in <var class="Fa">bitset</var> before setting only
    bit <var class="Fa">bit</var>.</p>
<p class="Pp" id="BIT_EMPTY">The
    <a class="permalink" href="#BIT_EMPTY"><code class="Fn">BIT_EMPTY</code></a>()
    macro returns <code class="Dv">true</code> if <var class="Fa">bitset</var>
    is empty.</p>
<p class="Pp" id="BIT_ISFULLSET">The
    <a class="permalink" href="#BIT_ISFULLSET"><code class="Fn">BIT_ISFULLSET</code></a>()
    macro returns <code class="Dv">true</code> if <var class="Fa">bitset</var>
    is full (all bits set).</p>
<p class="Pp" id="BIT_FFS">The
    <a class="permalink" href="#BIT_FFS"><code class="Fn">BIT_FFS</code></a>()
    macro returns the 1-index of the first (lowest) set bit in
    <var class="Fa">bitset</var>, or zero if <var class="Fa">bitset</var> is
    empty. Like with <a class="Xr">ffs(3)</a>, to use the non-zero result of
    <code class="Fn">BIT_FFS</code>() as a <var class="Fa">bit</var> index
    parameter to any other <code class="Nm">bitset(9)</code> macro, you must
    subtract one from the result.</p>
<p class="Pp" id="BIT_FFS_AT">The
    <a class="permalink" href="#BIT_FFS_AT"><code class="Fn">BIT_FFS_AT</code></a>()
    macro returns the 1-index of the first (lowest) set bit in
    <var class="Fa">bitset</var>, which is greater than the given 1-indexed
    <var class="Fa">start</var>, or zero if no bits in
    <var class="Fa">bitset</var> greater than <var class="Fa">start</var> are
    set.</p>
<p class="Pp" id="BIT_FLS">The
    <a class="permalink" href="#BIT_FLS"><code class="Fn">BIT_FLS</code></a>()
    macro returns the 1-index of the last (highest) set bit in
    <var class="Fa">bitset</var>, or zero if <var class="Fa">bitset</var> is
    empty. Like with <a class="Xr">fls(3)</a>, to use the non-zero result of
    <code class="Fn">BIT_FLS</code>() as a <var class="Fa">bit</var> index
    parameter to any other <code class="Nm">bitset(9)</code> macro, you must
    subtract one from the result.</p>
<p class="Pp" id="BIT_FOREACH_ISSET">The
    <a class="permalink" href="#BIT_FOREACH_ISSET"><code class="Fn">BIT_FOREACH_ISSET</code></a>()
    macro can be used to iterate over all set bits in
    <var class="Fa">bitset</var>. The index variable <var class="Fa">bit</var>
    must have been declared with type <var class="Ft">int</var>, and upon each
    iteration <var class="Fa">bit</var> is set to the index of successive set
    bits. The value of <var class="Fa">bit</var> after the loop terminates is
    undefined. Similarly,
    <a class="permalink" href="#BIT_FOREACH_ISCLR"><code class="Fn" id="BIT_FOREACH_ISCLR">BIT_FOREACH_ISCLR</code></a>()
    iterates over all clear bits in <var class="Fa">bitset</var>. In the loop
    body, the currently indexed bit may be set or cleared. However, setting or
    clearing bits other than the currently indexed bit does not guarantee that
    they will or will not be returned in subsequent iterations of the same
  loop.</p>
<p class="Pp" id="BIT_COUNT">The
    <a class="permalink" href="#BIT_COUNT"><code class="Fn">BIT_COUNT</code></a>()
    macro returns the total number of set bits in
  <var class="Fa">bitset</var>.</p>
<p class="Pp" id="BIT_SUBSET">The
    <a class="permalink" href="#BIT_SUBSET"><code class="Fn">BIT_SUBSET</code></a>()
    macro returns <code class="Dv">true</code> if <var class="Fa">needle</var>
    is a subset of <var class="Fa">haystack</var>.</p>
<p class="Pp" id="BIT_OVERLAP">The
    <a class="permalink" href="#BIT_OVERLAP"><code class="Fn">BIT_OVERLAP</code></a>()
    macro returns <code class="Dv">true</code> if <var class="Fa">bitset1</var>
    and <var class="Fa">bitset2</var> have any common bits. (That is, if
    <var class="Fa">bitset1</var> AND <var class="Fa">bitset2</var> is not the
    empty set.)</p>
<p class="Pp" id="BIT_CMP">The
    <a class="permalink" href="#BIT_CMP"><code class="Fn">BIT_CMP</code></a>()
    macro returns <code class="Dv">true</code> if <var class="Fa">bitset1</var>
    is NOT equal to <var class="Fa">bitset2</var>.</p>
<p class="Pp" id="BIT_OR">The
    <a class="permalink" href="#BIT_OR"><code class="Fn">BIT_OR</code></a>()
    macro sets bits present in <var class="Fa">src</var> in
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> |=
    <var class="Fa">src</var>.)
    <a class="permalink" href="#BIT_OR_ATOMIC"><code class="Fn" id="BIT_OR_ATOMIC">BIT_OR_ATOMIC</code></a>()
    is similar, but sets bits in the component machine words in
    <var class="Fa">dst</var> atomically. (That is, if <var class="Fa">dst</var>
    is composed of multiple machine words,
    <code class="Fn">BIT_OR_ATOMIC</code>() performs multiple individually
    atomic operations.)</p>
<p class="Pp" id="BIT_OR2">The
    <a class="permalink" href="#BIT_OR2"><code class="Fn">BIT_OR2</code></a>()
    macro computes <var class="Fa">src1</var> bitwise or
    <var class="Fa">src2</var> and assigns the result to
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> =
    <var class="Fa">src1</var> | <var class="Fa">src2</var>.)</p>
<p class="Pp" id="BIT_ORNOT">The
    <a class="permalink" href="#BIT_ORNOT"><code class="Fn">BIT_ORNOT</code></a>()
    macro sets bits not in <var class="Fa">src</var> in
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> |= <var class="Fa">~
    src</var>.)</p>
<p class="Pp" id="BIT_ORNOT2">The
    <a class="permalink" href="#BIT_ORNOT2"><code class="Fn">BIT_ORNOT2</code></a>()
    macro computes <var class="Fa">src1</var> bitwise or not
    <var class="Fa">src2</var> and assigns the result to
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> =
    <var class="Fa">src1</var> | ~ <var class="Fa">src2</var>.)</p>
<p class="Pp" id="BIT_AND">The
    <a class="permalink" href="#BIT_AND"><code class="Fn">BIT_AND</code></a>()
    macro clears bits absent from <var class="Fa">src</var> from
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> &amp;=
    <var class="Fa">src</var>.)
    <a class="permalink" href="#BIT_AND_ATOMIC"><code class="Fn" id="BIT_AND_ATOMIC">BIT_AND_ATOMIC</code></a>()
    is similar, with the same atomic semantics as
    <code class="Fn">BIT_OR_ATOMIC</code>().</p>
<p class="Pp" id="BIT_AND2">The
    <a class="permalink" href="#BIT_AND2"><code class="Fn">BIT_AND2</code></a>()
    macro computes <var class="Fa">src1</var> bitwise and
    <var class="Fa">src2</var> and assigns the result to
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> =
    <var class="Fa">src1</var> &amp; <var class="Fa">src2</var>.)</p>
<p class="Pp" id="BIT_ANDNOT">The
    <a class="permalink" href="#BIT_ANDNOT"><code class="Fn">BIT_ANDNOT</code></a>()
    macro clears bits set in <var class="Fa">src</var> from
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> &amp;= <var class="Fa">~
    src</var>.)</p>
<p class="Pp" id="BIT_ANDNOT2">The
    <a class="permalink" href="#BIT_ANDNOT2"><code class="Fn">BIT_ANDNOT2</code></a>()
    macro computes <var class="Fa">src1</var> bitwise and not
    <var class="Fa">src2</var> and assigns the result to
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> =
    <var class="Fa">src1</var> &amp; ~ <var class="Fa">src2</var>.)</p>
<p class="Pp" id="BIT_XOR">The
    <a class="permalink" href="#BIT_XOR"><code class="Fn">BIT_XOR</code></a>()
    macro toggles bits set in <var class="Fa">src</var> in
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> ^=
    <var class="Fa">src</var>.)</p>
<p class="Pp" id="BIT_XOR2">The
    <a class="permalink" href="#BIT_XOR2"><code class="Fn">BIT_XOR2</code></a>()
    macro computes <var class="Fa">src1</var> bitwise exclusive or
    <var class="Fa">src2</var> and assigns the result to
    <var class="Fa">dst</var>. (It is the <code class="Nm">bitset(9)</code>
    equivalent of the scalar: <var class="Fa">dst</var> =
    <var class="Fa">src1</var> ^ <var class="Fa">src2</var>.)</p>
</section>
<section class="Sh">
<h1 class="Sh" id="BITSET_T_INITIALIZER_EXAMPLE"><a class="permalink" href="#BITSET_T_INITIALIZER_EXAMPLE">BITSET_T_INITIALIZER
  EXAMPLE</a></h1>
<div class="Bd Li">
<pre>BITSET_DEFINE(_myset, MYSETSIZE);

struct _myset myset;

/* Initialize myset to filled (all bits set) */
myset = BITSET_T_INITIALIZER(BITSET_FSET(__bitset_words(MYSETSIZE)));

/* Initialize myset to only the lowest bit set */
myset = BITSET_T_INITIALIZER(0x1);</pre>
</div>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">bitstring(3)</a>, <a class="Xr">cpuset(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">bitset(9)</code> macros first appeared in
    <span class="Ux">FreeBSD 10.0</span> in January 2014. They were MFCed to
    <span class="Ux">FreeBSD 9.3</span>, released in July 2014.</p>
<p class="Pp">This manual page first appeared in <span class="Ux">FreeBSD
    11.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The <code class="Nm">bitset(9)</code> macros were generalized and
    pulled out of <code class="In">&lt;<a class="In">sys/cpuset.h</a>&gt;</code>
    as <code class="In">&lt;<a class="In">sys/_bitset.h</a>&gt;</code> and
    <code class="In">&lt;<a class="In">sys/bitset.h</a>&gt;</code> by
    <span class="An">Attilio Rao</span>
    &lt;<a class="Mt" href="mailto:attilio@FreeBSD.org">attilio@FreeBSD.org</a>&gt;.
    This manual page was written by <span class="An">Conrad Meyer</span>
    &lt;<a class="Mt" href="mailto:cem@FreeBSD.org">cem@FreeBSD.org</a>&gt;.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="CAVEATS"><a class="permalink" href="#CAVEATS">CAVEATS</a></h1>
<p class="Pp">The <var class="Fa">SETSIZE</var> argument to all of these macros
    must match the value given to <code class="Fn">BITSET_DEFINE</code>().</p>
<p class="Pp">Unlike every other reference to individual set members, which are
    zero-indexed, <code class="Fn">BIT_FFS</code>(),
    <code class="Fn">BIT_FFS_AT</code>() and <code class="Fn">BIT_FLS</code>()
    return a one-indexed result (or zero if the set is empty).</p>
<p class="Pp">In order to use the macros defined in
    <code class="In">&lt;<a class="In">sys/bitset.h</a>&gt;</code> and
    <code class="In">&lt;<a class="In">sys/_bitset.h</a>&gt;</code> in userland
    programs, <code class="Dv">_WANT_FREEBSD_BITSET</code> has to be defined
    before including the header files. This requirements exists to prevent a
    name space pollution due to macros defined in
    <code class="Nm">bitset(9)</code> in programs that include
    <code class="In">&lt;<a class="In">sys/cpuset.h</a>&gt;</code> or
    <code class="In">&lt;<a class="In">sched.h</a>&gt;</code>.</p>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">September 20, 2021</td>
    <td class="foot-os">FreeBSD 15.0</td>
  </tr>
</table>