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    <title>barrier</title>
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    <meta name="keywords" content="                            &#10;                Synchronization, barrier&#10;            " />
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      <div xmlns="" class="refnamediv">
        <a xmlns="http://www.w3.org/1999/xhtml" id="barrier"></a>
        <h1>barrier</h1>
        <p>
            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. 
        </p>
      </div>
      <div class="refsynopsisdiv">
        <h2></h2>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
            <tr valign="bottom">
              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    <a class="link" href="scalarDataTypes.html" target="_top">void</a>
                    <strong class="fsfunc">                   
                        barrier
                    </strong>
                (</code>
                <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="_top">cl_mem</a>_fence_flags <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">flags</var><code>)</code></td>
              </td>
            </tr>
          </table>
        </div>
      </div>
      <div class="refsect1">
        <a id="description"></a>
        <h2>Description</h2>
        <p>
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.
This function must be encountered by all work-items in
a work-group executing the kernel.
		</p>
        <p>
		</p>
        <p>
If <code class="function">barrier</code> is inside a conditional statement, then all
work-items must enter the conditional if any work-item
enters the conditional statement and executes the
<code class="function">barrier</code>.
		</p>
        <p>
		</p>
        <p>
If <code class="function">barrier</code> is inside a loop, all work-items must execute
the <code class="function">barrier</code> for each iteration of the loop before any are
allowed to continue execution beyond the <code class="function">barrier</code>.
		</p>
        <p>
		</p>
        <p>
The <code class="function">barrier</code> function also queues a memory fence
(reads and writes) to ensure correct ordering of
memory operations to local or global memory.
		</p>
        <p>
		</p>
        <p>
The <code class="varname">flags</code> argument specifies the memory address space
and can be set to a combination of the following literal
values.
		</p>
        <p>
		</p>
        <p>
CLK_LOCAL_MEM_FENCE - The <code class="function">barrier</code> function
will either flush any variables stored in local memory
or queue a memory fence to ensure correct ordering of
memory operations to local memory.
		</p>
        <p>
		</p>
        <p>
CLK_GLOBAL_MEM_FENCE - The <code class="function">barrier</code> function
will queue a memory fence to ensure correct ordering
of memory operations to global memory. This can be
useful when work-items, for example, write to buffer or
image objects and then want to read the updated data.
		</p>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />
                                                 
            <a href="http://www.khronos.org/registry/cl/specs/opencl-1.0.pdf#page=199" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p>Copyright © 2007-2009 The Khronos Group Inc. 
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials. 
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