sdk/1.0/docs/man/barrier.xml

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<refentry>
    <refentryinfo>
        <keywordset>
            <keyword>                            
                Synchronization, barrier
            </keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>                                    
        <refentrytitle>barrier</refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2009</year>
                <holder>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,
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permit persons to whom the Materials are furnished to do so, subject to
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in all copies or substantial portions of the Materials.</holder>
            </copyright>
        </refmiscinfo>
        <manvolnum>2</manvolnum>
    </refmeta>

<!-- ================================ SYNOPSIS -->

    <refnamediv id="barrier">             
        <refname>barrier</refname>

        <refpurpose>
            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. 
        </refpurpose>
    </refnamediv>

	<refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>
                    <link xlink:href="scalarDataTypes.html">void</link>
                    <function>                   
                        barrier
                    </function>
                </funcdef>
				<paramdef><link xlink:href="abstractDataTypes.html">cl_mem</link>_fence_flags<parameter>flags</parameter></paramdef>	
            </funcprototype>
        </funcsynopsis>     
	</refsynopsisdiv>		

<!-- ================================ DESCRIPTION  -->

    <refsect1 id="description"><title>Description</title>
        <para>
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.
		<para>
		</para>
If <function>barrier</function> is inside a conditional statement, then all
work-items must enter the conditional if any work-item
enters the conditional statement and executes the
<function>barrier</function>.
		<para>
		</para>
If <function>barrier</function> is inside a loop, all work-items must execute
the <function>barrier</function> for each iteration of the loop before any are
allowed to continue execution beyond the <function>barrier</function>.
		<para>
		</para>
The <function>barrier</function> function also queues a memory fence
(reads and writes) to ensure correct ordering of
memory operations to local or global memory.
		<para>
		</para>
The <varname>flags</varname> argument specifies the memory address space
and can be set to a combination of the following literal
values.
		<para>
		</para>
CLK_LOCAL_MEM_FENCE - The <function>barrier</function> 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.
		<para>
		</para>
CLK_GLOBAL_MEM_FENCE - The <function>barrier</function> 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.
		</para>
    </refsect1>

<!-- ================================ NOTES  
    <refsect1 id="notes"><title>Notes</title>
        <para>

		</para>
	</refsect1>-->
<!-- ================================ EXAMPLE  -->
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<!-- ================================ SPECIFICATION  -->
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        <para>
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            </imageobject>
                                                 
            <olink uri="synchFunctions">OpenCL Specification</olink>
        </para>
    </refsect1>


<!-- ================================ ALSO SEE  -->
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    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry href="imageFunctions"><refentrytitle>Image Functions</refentrytitle></citerefentry> 
        </para>
    </refsect1>-->



<!-- ============================== COPYRIGHT -->
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