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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
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"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
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<keyword>Synchronization, barrier</keyword>
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<refentrytitle>barrier</refentrytitle>
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<year>2007-2011</year>
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<holder>The Khronos Group Inc.
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Permission is hereby granted, free of charge, to any person obtaining a
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copy of this software and/or associated documentation files (the
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"Materials"), to deal in the Materials without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Materials, and to
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permit persons to whom the Materials are furnished to do so, subject to
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the condition that this copyright notice and permission notice shall be included
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in all copies or substantial portions of the Materials.</holder>
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<manvolnum>3</manvolnum>
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<!-- ================================ SYNOPSIS -->
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<refnamediv id="barrier">
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<refname>barrier</refname>
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All work-items in a work-group executing the kernel on a processor must execute this function before any are allowed to continue execution beyond the barrier.
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<refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
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<link xlink:href="scalarDataTypes.html">void</link>
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<paramdef><link xlink:href="enums.html#cl_mem_fence_flags">cl_mem_fence_flags</link><parameter>flags</parameter></paramdef>
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<!-- ================================ DESCRIPTION -->
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<refsect1 id="description"><title>Description</title>
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All work-items in a work-group executing the kernel on a processor must execute
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this function before any are allowed to continue execution beyond the barrier.
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This function must be encountered by all work-items in a work-group executing the kernel.
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If <function>barrier</function> is inside a conditional statement, then all work-items
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must enter the conditional if any work-item enters the conditional statement and
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executes the <function>barrier</function>.
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If <function>barrier</function> is inside a loop, all work-items must execute the
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<function>barrier</function> for each iteration of the loop before any are allowed
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to continue execution beyond the <function>barrier</function>.
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The <function>barrier</function> function also queues a memory fence (reads and writes)
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to ensure correct ordering of memory operations to local or global memory.
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The <varname>flags</varname> argument specifies the memory address space and can be
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set to a combination of the following literal values.
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<constant>CLK_LOCAL_MEM_FENCE</constant> - The <function>barrier</function> function
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will either flush any variables stored in local memory or queue a memory fence to
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ensure correct ordering of memory operations to local memory.
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<constant>CLK_GLOBAL_MEM_FENCE</constant> - The <function>barrier</function> function
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will queue a memory fence to ensure correct ordering of memory operations to global
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memory. This can be useful when work-items, for example, write to buffer or image
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objects and then want to read the updated data.
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<!-- ================================ NOTES
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<refsect1 id="notes"><title>Notes</title>
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<!-- ================================ EXAMPLE -->
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<refsect2 id="example1">
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Example goes here - it will be set in "code" type with white space preserved.
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<!-- ================================ SPECIFICATION -->
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<!-- Set the "uri" attribute in the <olink /> element to the "named destination" for the PDF page
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<refsect1 id="specification"><title>Specification</title>
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<imagedata fileref="pdficon_small1.gif" format="gif" />
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<olink uri="synchFunctions">OpenCL Specification</olink>
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<!-- ================================ ALSO SEE -->
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<!-- Enter comma-delimited list of all other pages in the system to link to, using
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<citerefentry /><refentrytitle /> to make it a link. For any case where the text of the link needs to differ
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from the filename of the html file this links to, use the "href" attribute in <citerefentry />. For example:
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<citerefentry href="thatPage"><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry>
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<refsect1 id="seealso"><title>Also see</title>
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<citerefentry href="imageFunctions"><refentrytitle>Image Functions</refentrytitle></citerefentry>
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<!-- ============================== COPYRIGHT -->
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<!-- Content included from copyright.inc.xsl -->
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<refsect3 id="Copyright"><title></title>
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