<div class="refentry" id="barrier">

<div class="titlepage"></div>

<div class="refnamediv">

<h2>Name</h2>

<p>barrier — synchronize execution of multiple shader invocations</p>

</div>

<div class="refsynopsisdiv">

<h2>Declaration</h2>

<div class="funcsynopsis">

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<code class="funcdef">void <strong class="fsfunc">barrier</strong>(</code>

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<td>void<code>)</code>;</td>

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<div class="refsect1" id="description">

<h2>Description</h2>

<p>

<span class="emphasis"><em>Available only in the Compute Shader</em></span>, <code class="function">barrier</code> provides

a partially defined order of execution between shader invocations. For any given static instance of

<code class="function">barrier</code> in a compute shader, all invocations within a single work group must

enter it before any are allowed to continue beyond it.

This ensures that values written by one invocation prior to a given static instance

of <code class="function">barrier</code> can be safely read by other invocations after their call to the same static

instance of <code class="function">barrier</code>. Because invocations may execute in undefined order between these

<code class="function">barrier</code> calls, the values of any shared variable will be undefined in a number of cases.

</p>

<p>

<code class="function">barrier</code> may be placed anywhere in a compute shader, except within any control flow or

after a return statement in the function <code class="code">main()</code>.

</p>

</div>

{$pipelinestall}{$examples}

<div class="refsect1" id="versions">

<h2>Version Support</h2>

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<col style="text-align: center; " class="firstvers"/>

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<col style="text-align: center; " class="lastvers"/>

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<th style="text-align: left; border-right: 2px solid ; ">

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<th style="text-align: center; border-bottom: 2px solid ; " colspan="3">

<span class="bold"><strong>OpenGL ES Shading Language Version</strong></span>

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<span class="bold"><strong>Function Name</strong></span>

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<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">

<span class="bold"><strong>1.00</strong></span>

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<th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">

<span class="bold"><strong>3.00</strong></span>

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<th style="text-align: center; border-bottom: 2px solid ; ">

<span class="bold"><strong>3.10</strong></span>

</th>

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</thead>

<tbody>

<tr>

<td style="text-align: left; border-right: 2px solid ; ">

<code class="function">barrier</code>

</td>

<td style="text-align: center; border-right: 2px solid ; ">-</td>

<td style="text-align: center; border-right: 2px solid ; ">-</td>

<td style="text-align: center; ">✔</td>

</tr>

</tbody>

</table>

</div>

</div>

<div class="refsect1" id="Copyright">

<h2>Copyright</h2>

<p>

Copyright © 2011-2014 Khronos Group.

This material may be distributed subject to the terms and conditions set forth in

the Open Publication License, v 1.0, 8 June 1999.

<a class="link" href="https://opencontent.org/openpub/" target="_top">https://opencontent.org/openpub/</a>.

</p>

</div>

</div>