sdk/2.0/docs/man/memory_scope.xml

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<refentry>
    <refentryinfo>
        <keywordset>
            <keyword>memory_scope</keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>
        <refentrytitle>memory_scope</refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2013</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,
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.</holder>
            </copyright>
        </refmiscinfo>
        <manvolnum>3</manvolnum>
    </refmeta>

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

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

        <refpurpose>
            Identify if memory_scope applies to work-items in a work-group or work-items of a kernel(s).
        </refpurpose>
    </refnamediv>

    <!-- ALTERNATIVE SYNTAX SYNOPSIS (NON-FUNCTION) -->

    <refsect2 id="synopsis">
        <title>
        </title>

        <informaltable frame="none">
            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
                <tbody>
                    <row>
                        <entry>
memory_scope
                        </entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect2>

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

    <refsect1 id="description"><title>Description</title>

<!-- general atomic functions info -->

        <para>
            The OpenCL C programming language implements a subset of the C11 atomics (refer to section 
            7.17 of the C11 specification) and synchronization operations. These operations play a special 
            role in making assignments in one work-item visible to another.
            A synchronization operation on 
            one or more memory locations is either an acquire operation, a release operation, or both an 
            acquire and release operation. (The C11 consume operation is not supported.)
            A synchronization operation without an associated memory 
            location is a fence and can be either an acquire fence, a release fence or both an acquire and 
            release fence. In addition, there are relaxed atomic operations, which are not synchronization 
            operations, and atomic read-modify-write operations which have special characteristics
        </para>

<!-- start of memory_scope-specific text -->

        <para>
            The enumerated type <type>memory_scope</type> specifies 
            whether the memory ordering constraints given by 
            <citerefentry><refentrytitle>memory_order</refentrytitle></citerefentry> 
            apply to work-items in a work-group or work-items of a kernel(s) 
            executing on the device or across devices (in the case of shared virtual memory).
            Its enumeration constants are as follows:
        </para>

        <para>
<literallayout><code>     <constant>memory_scope_work_item</constant>
     <constant>memory_scope_work_group</constant>
     <constant>memory_scope_device</constant>
     <constant>memory_scope_all_svm_devices</constant>
     <constant>memory_scope_sub_group</constant></code> (if <citerefentry><refentrytitle>cl_khr_subgroups</refentrytitle></citerefentry> is supported)</literallayout>
        </para>

        <para>
            The <constant>memory_scope_work_item</constant> value for 
            <type>memory_scope</type> can only be used with 
            <function>atomic_work_item_fence</function> with 
            <varname>flags</varname> set to 
            <constant>CLK_IMAGE_MEM_FENCE</constant>.
        </para>

        <para>
            The memory scope should only be used when performing atomic operations to global memory. 
            Atomic operations to local memory only guarantee memory ordering in the work-group not 
            across work-groups and therefore ignore the <type>memory_scope</type> value.
        </para>

        <para>
            If the
            <citerefentry><refentrytitle>cl_khr_subgroups</refentrytitle></citerefentry>
            extension is enabled, The <constant>memory_scope_sub_group</constant> 
            specifies that the memory ordering constraints given by memory_order 
            apply to work-items in a sub-group. This memory scope can be used 
            when performing atomic operations to global or local memory.
        </para>

    </refsect1>

<!-- ================================ NOTES  -->

    <refsect1 id="notes"><title>Notes</title>
        <para>
        </para>

    </refsect1>

<!-- ================================ EXAMPLE  -->

<!--
    <refsect2 id="example1">
        <title>
            Example
        </title>

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                        <entry>
example code
                        </entry>
                    </row>
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        </informaltable>
    </refsect2>
-->

<!-- ================================ SPECIFICATION  -->
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    <refsect1 id="specification"><title>Specification</title>
        <para>
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            <olink uri="memory_scope">OpenCL Specification</olink>
        </para>
    </refsect1>

<!-- ================================ ALSO SEE  -->
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    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry href="atomicFunctions"><refentrytitle>Atomic Functions</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>memory_order</refentrytitle></citerefentry>
        </para>
    </refsect1>

<!-- ============================== COPYRIGHT -->
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    <refsect3 id="Copyright"><title></title>
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        <para />
    </refsect3>

<!-- 23-Dec-2013, rev. 19 -->
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