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<div class="refnamediv">
<h1 class="refname">gmp_setbit</h1>
<p class="verinfo">(PHP 4 >= 4.0.4, PHP 5)</p><p class="refpurpose"><span class="refname">gmp_setbit</span> — <span class="dc-title">Set bit</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.gmp-setbit-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><span class="type void">void</span></span> <span class="methodname"><strong>gmp_setbit</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter reference">&$a</code></span>
, <span class="methodparam"><span class="type">int</span> <code class="parameter">$index</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$bit_on</code><span class="initializer"> = true</span></span>
] )</div>
<p class="para rdfs-comment">
Sets bit <em><code class="parameter">index</code></em> in <em><code class="parameter">a</code></em>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.gmp-setbit-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">a</code></em></span>
<dd>
<p class="para">
The value to modify.
</p>
<p class="para">It can be either a GMP number <span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span>, or a
numeric string given that it is possible to convert the latter to a number.</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">index</code></em></span>
<dd>
<p class="para">
The index of the bit to set. Index 0 represents the least significant bit.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">bit_on</code></em></span>
<dd>
<p class="para">
True to set the bit (set it to 1/on); false to clear the bit (set it to 0/off).
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.gmp-setbit-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
A GMP number <span class="type"><a href="language.types.resource.html" class="type resource">resource</a></span>.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.gmp-setbit-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3431">
<p><strong>Example #1 <span class="function"><strong>gmp_setbit()</strong></span> example - 0 index</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$a </span><span style="color: #007700">= </span><span style="color: #0000BB">gmp_init</span><span style="color: #007700">(</span><span style="color: #DD0000">"2"</span><span style="color: #007700">); </span><span style="color: #FF8000">//<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">' -> 0b'</span><span style="color: #007700">, </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">gmp_setbit</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">); </span><span style="color: #FF8000">// 0b10 now becomes 0b11<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">' -> 0b'</span><span style="color: #007700">, </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
2 -> 0b10
3 -> 0b11
</pre></div>
</div>
</div>
<div class="example" id="example-3432">
<p><strong>Example #2 <span class="function"><strong>gmp_setbit()</strong></span> example - 1 index</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$a </span><span style="color: #007700">= </span><span style="color: #0000BB">gmp_init</span><span style="color: #007700">(</span><span style="color: #DD0000">"0xfd"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">' -> 0b'</span><span style="color: #007700">, </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">gmp_setbit</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">); </span><span style="color: #FF8000">// index starts at 0<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">' -> 0b'</span><span style="color: #007700">, </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
253 -> 0b11111101
255 -> 0b11111111
</pre></div>
</div>
</div>
<div class="example" id="example-3433">
<p><strong>Example #3 <span class="function"><strong>gmp_setbit()</strong></span> example - clearing a bit</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$a </span><span style="color: #007700">= </span><span style="color: #0000BB">gmp_init</span><span style="color: #007700">(</span><span style="color: #DD0000">"0xff"</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">' -> 0b'</span><span style="color: #007700">, </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">gmp_setbit</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">false</span><span style="color: #007700">); </span><span style="color: #FF8000">// clear bit at index 0<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">), </span><span style="color: #DD0000">' -> 0b'</span><span style="color: #007700">, </span><span style="color: #0000BB">gmp_strval</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
255 -> 0b11111111
254 -> 0b11111110
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.gmp-setbit-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Unlike most of the other GMP functions, <span class="function"><strong>gmp_setbit()</strong></span>
must be called with a GMP resource that already exists (using
<span class="function"><a href="function.gmp-init.html" class="function">gmp_init()</a></span> for example). One will not be
automatically created.
</p>
</p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.gmp-setbit-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.gmp-clrbit.html" class="function" rel="rdfs-seeAlso">gmp_clrbit()</a> - Clear bit</span></li>
<li class="member"> <span class="function"><a href="function.gmp-testbit.html" class="function" rel="rdfs-seeAlso">gmp_testbit()</a> - Tests if a bit is set</span></li>
</ul>
</p>
</div>
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