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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">[
<!ENTITY qualifierInc SYSTEM "qualifierInc.xml">
<!ENTITY qualifierExampleInc SYSTEM "qualifierExampleInc.xml">
]>
<refentry>
<refentryinfo>
<keywordset>
<keyword>__global</keyword>
</keywordset>
</refentryinfo>
<refmeta>
<refentrytitle>__global</refentrytitle>
<refmiscinfo>
<copyright>
<year>2007-2011</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="__global">
<refname>__global</refname>
<refpurpose>
Address space qualifier.
</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>
__global
global
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect2>
<!-- ================================ DESCRIPTION -->
<refsect1 id="description"><title>Description</title>
&qualifierInc;
</refsect1>
<!-- ================================ NOTES -->
<refsect1 id="notes"><title>Notes</title>
<para>
The <function>__global</function> or <function>global</function> address
space name is used to refer to memory objects (buffer or image objects)
allocated from the global memory pool.
</para>
<para>
A buffer memory object can be declared as a pointer to a scalar, vector
or user-defined struct. This allows the kernel to read and/or write any
location in the buffer.
</para>
<para>
The actual size of the array memory object is determined when the memory
object is allocated via appropriate API calls in the host code.
</para>
<para>
If an image object is attached to an argument declared with this qualifier,
the argument must be declared as type
<type><citerefentry href="otherDataTypes"><refentrytitle>image2d_t</refentrytitle></citerefentry></type>
for a 2D image object, as type
<type><citerefentry href="otherDataTypes"><refentrytitle>image3d_t</refentrytitle></citerefentry></type>
for a 3D image object, as type
<type><citerefentry href="otherDataTypes"><refentrytitle>image2d_array_t</refentrytitle></citerefentry></type>
for a 2D image array object, as type
<type><citerefentry href="otherDataTypes"><refentrytitle>image1d_t</refentrytitle></citerefentry></type>
for a 1D image object, as type
<type><citerefentry href="otherDataTypes"><refentrytitle>image1d_buffer_t</refentrytitle></citerefentry></type>
for a 1D image buffer object, and as type
<type><citerefentry href="otherDataTypes"><refentrytitle>image1d_array_t</refentrytitle></citerefentry></type>
for a 1D image array object. The elements of an image object cannot be directly accessed.
Built-in functions to read from and write to an image object are provided.
</para>
<para>
The const qualifier can also be used with the <function>__global</function> qualifier to
specify a read-only buffer memory object.
</para>
</refsect1>
<!-- ================================ EXAMPLE -->
<refsect2 id="example1">
<title>
Examples
</title>
&qualifierExampleInc;
<informaltable frame="none">
<tgroup cols="1" align="left" colsep="0" rowsep="0">
<colspec colname="col1" colnum="1" />
<tbody>
<row>
<entry>
__global float4 *color; // An array of float4 elements
typedef struct {
float a[3];
int b[2];
} foo_t;
__global foo_t *my_info; // An array of foo_t elements.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect2>
<!-- ================================ SPECIFICATION -->
<!-- Set the "uri" attribute in the <olink /> element to the "named destination" for the PDF page
-->
<refsect1 id="specification"><title>Specification</title>
<para>
<imageobject>
<imagedata fileref="pdficon_small1.gif" format="gif" />
</imageobject>
<olink uri="addressSpaceQualifier">OpenCL Specification</olink>
</para>
</refsect1>
<!-- ================================ ALSO SEE -->
<refsect1 id="seealso"><title>Also see</title>
<para>
<citerefentry href="local"><refentrytitle>__local</refentrytitle></citerefentry>,
<citerefentry href="constant"><refentrytitle>__constant</refentrytitle></citerefentry>,
<citerefentry href="private"><refentrytitle>__private</refentrytitle></citerefentry>
</para>
</refsect1>
<!-- ============================== COPYRIGHT -->
<!-- Content included from copyright.inc.xsl -->
<refsect3 id="Copyright"><title></title>
<imageobject>
<imagedata fileref="KhronosLogo.jpg" format="jpg" />
</imageobject>
<para />
</refsect3>
<!-- 16-Oct-2011 -->
</refentry>
|
