sdk/1.0/docs/man/clCreateContextFromType.xml

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<refentry>
    <refentryinfo>
        <keywordset>
            <keyword>         
                clCreateContextFromType
            </keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>
        <refentrytitle>       
            clCreateContextFromType
        </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,
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>2</manvolnum>
  
    </refmeta>


<!-- ================================ SYNOPSIS -->  
    <refnamediv id="clCreateContextFromType">
        <refname>              
            clCreateContextFromType 
        </refname> 

        <refpurpose>          
            Create an OpenCL context from a device type that identifies the specific device(s) to use.
        </refpurpose>
    </refnamediv> 

    <refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>

                    cl_context

                    <function>      
                        clCreateContextFromType
                    </function>
                </funcdef>

                <paramdef><type><link xlink:href="enums.html#cl_context_properties">cl_context_properties</link></type>
					<parameter> *properties</parameter></paramdef>
                <paramdef><link xlink:href="enums.html#cl_device_type">cl_device_type</link> 
					<parameter>device_type</parameter></paramdef>
                <paramdef><link xlink:href="scalarDataTypes.html">void</link> 
					<parameter>(*pfn_notify)
						(const <link xlink:href="scalarDataTypes.html">char</link> *errinfo</parameter></paramdef>
          		<paramdef>const <link xlink:href="scalarDataTypes.html">void</link> 
		  			<parameter>*private_info</parameter></paramdef> 
          		<paramdef><link xlink:href="scalarDataTypes.html">size_t</link> 
					<parameter>cb</parameter></paramdef>  
				<paramdef><link xlink:href="scalarDataTypes.html">void</link>
					<parameter>*user_data)</parameter></paramdef>
                <paramdef><link xlink:href="scalarDataTypes.html">void</link>
					<parameter>*user_data</parameter></paramdef>
                <paramdef><link xlink:href="scalarDataTypes.html">cl_int</link>
					<parameter>*errcode_ret</parameter></paramdef>     

            </funcprototype>
        </funcsynopsis>     
    </refsynopsisdiv>


<!-- ================================ PARAMETERS --> 

    <refsect1 id="parameters">
        <title>Parameters</title>
        <variablelist>

        
<!-- ================================ PARAMETER TABLE (OPTIONAL) -->		
        <varlistentry>
            <term>properties</term>
            <listitem>
				<para>
                    Specifies a list of context property names and their corresponding values. Each property name is immediately followed by the corresponding desired value. The list is terminated with 0. <varname>properties</varname> can be NULL in which case the platform that is selected is implementation-defined. The list of supported properties is described in the table below. 
                </para>
				<informaltable frame="all"><tgroup cols="3" align="left" colsep="1" rowsep="1">
	<colspec colname="col1" colnum="1" />
	<colspec colname="col2" colnum="2" />
	<colspec colname="col3" colnum="3" />	
	<thead>
		<row>
		<entry>cl_context_properties enum</entry>
		<entry>Property value</entry>		
		<entry>Description</entry>
		</row>
	</thead>
	<tbody>
		<row>
			<entry><constant>CL_CONTEXT_PLATFORM</constant></entry>
			<entry><link xlink:href="abstractDataTypes.html">cl_platform_id</link></entry>
			<entry>Specifies the platform to use.</entry>
		</row>
	</tbody>	
		
	</tgroup></informaltable>	
            </listitem>
        </varlistentry>
<!-- ================================ END PARAMETER TABLE  -->	           

<!-- ================================ PARAMETER TABLE (OPTIONAL) -->		
        <varlistentry>
            <term>device_type</term>
            <listitem>
				<para>
                    A bit-field that identifies the type of device and is described in the table below. 
                </para>
				<informaltable frame="all"><tgroup cols="2" align="left" colsep="1" rowsep="1">
	<colspec colname="col1" colnum="1" />
	<colspec colname="col2" colnum="2" />
	<thead>
		<row>
		<entry>cl_device_type</entry>
		<entry>Description</entry>
		</row>
	</thead>
	<tbody>
		<row>
			<entry><constant>CL_DEVICE_TYPE_CPU</constant></entry>
			<entry>An OpenCL device that is the host processor. The host
processor runs the OpenCL implementations and is a
single or multi-core CPU.</entry>
		</row>
		<row>
			<entry><constant>CL_DEVICE_TYPE_GPU</constant></entry>
			<entry>An OpenCL device that is a GPU. By this we mean that
the device can also be used to accelerate a 3D API such
as OpenGL or DirectX.</entry>
		</row>
		<row>
			<entry><constant>CL_DEVICE_TYPE_ACCELERATOR</constant></entry>
			<entry>Dedicated OpenCL accelerators (for example the IBM
CELL Blade). These devices communicate with the host
processor using a peripheral interconnect such as PCIe.</entry>
		</row>
		
		<row>
			<entry><constant>CL_DEVICE_TYPE_DEFAULT</constant></entry>
			<entry>The default OpenCL device in the system.</entry>
		</row>
		<row>
			<entry><constant>CL_DEVICE_TYPE_ALL</constant></entry>
			<entry>All OpenCL devices available in the system.</entry>
		</row>
	</tbody>	
		
	</tgroup></informaltable>
            </listitem>
        </varlistentry>
<!-- ================================ END PARAMETER TABLE  -->

            <varlistentry>
            <term><varname>pfn_notify</varname></term>
            <listitem>
                <para>
                    A callback function that can be registered by the application. This callback function will be used by the OpenCL implementation to report information on errors that occur in this context. This callback function may be called asynchronously by the OpenCL implementation.
It is the application's responsibility to ensure that the callback function is thread-safe. If <varname>pfn_notify</varname> is NULL, no callback function is registered. The parameters to this callback function are:
                </para>
				
				<para><varname>errinfo</varname> is a pointer to an error string.</para>
<para><varname>private_info</varname> and <varname>cb</varname> represent a pointer to binary data that is returned by the OpenCL implementation that can be used to log additional information helpful in debugging the error.</para>
<para><varname>user_data</varname> is a pointer to user supplied data.</para>
            </listitem>
        </varlistentry>
		<varlistentry>
            <term><varname>user_data</varname></term>
            <listitem>
                <para>
                    Passed as the <varname>user_data</varname> argument when <varname>pfn_notify</varname> is called. user_data can be NULL.
                </para>
            </listitem>
        </varlistentry>

            <varlistentry>
                <term>
                    <varname> <!-- parameter name -->
                        errcode_ret
                    </varname>
                </term>

                <listitem>
                    <para> <!-- parameter description -->
                        Return an appropriate error code. If errcode_ret is NULL, no error code is returned.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsect1>


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

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

            may return all or a subset of the actual physical devices present in the platform and that match <varname>device_type</varname>.
        </para>
		<para>
            <function>clCreateContextFromType</function> and <citerefentry><refentrytitle>clCreateContext</refentrytitle></citerefentry> perform an implicit retain. This is very helpful for 3rd party libraries, which typically get a context passed to them by the application.
However, it is possible that the application may delete the context without informing the library.
Allowing functions to attach to (i.e. retain) and release a context solves the problem of a context
being used by a library no longer being valid.
        </para>
    </refsect1>
 
    
<!-- ================================ ERRORS  -->       
 

    <refsect1 id="errors"><title>Errors</title>
        <para>
            <function>clCreateContextFromType</function> returns a valid non-zero context and <varname>errcode_ret</varname> is set to <errorname>CL_SUCCESS</errorname> if the context is created successfully. Otherwise, it returns a NULL value with the following error vlaues returned in <varname>errcode_ret</varname>:
        </para>

        <itemizedlist mark="disc">
            <listitem>
                <errorname>CL_INVALID_PLATFORM</errorname> if <varname>properties</varname> is NULL and no platform could be selected or if platform value specified in <varname>properties</varname> is not a valid platform.
            </listitem>

            <listitem>
                <errorname>CL_INVALID_VALUE</errorname> if context property name in <varname>properties</varname> is not a supported property name, or if <varname>pfn_notify</varname> is NULL but user_data is not NULL. 
            </listitem>

            <listitem>
                <errorname>CL_INVALID_VALUE</errorname> if <varname>pfn_notify</varname> is NULL but <varname>user_data</varname> is not NULL.
            </listitem>
 
            <listitem>
                <errorname>CL_DEVICE_NOT_AVAILABLE</errorname> if no devices that match <varname>device_type</varname> are currently available.
            </listitem>

            <listitem>
                <errorname>CL_DEVICE_NOT_FOUND</errorname> if no devices that match <varname>device_type</varname> were found.
            </listitem>

            <listitem>
                <errorname>CL_OUT_OF_HOST_MEMORY</errorname> if there is a failure to allocate resources required by the OpenCL implementation on the host.
            </listitem>

            <listitem>
                <errorname>CL_INVALID_DEVICE_TYPE</errorname> if <varname>device_type</varname> is not a valid value.
            </listitem>
        </itemizedlist>
    </refsect1>
    

<!-- ================================ EXAMPLE  -->  
<!-- DO NOT DELETE IN CASE AN EXAMPLE IS ADDED IN THE FUTURE -->
<!--    --> 
    <refsect2 id="example1">
        <title>
            Example
        </title>

        <informaltable frame="none">
            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
                <tbody>
                    <row>
                        <entry>Example goes here - it will be set in "code" type with white space preserved.</entry>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>   
    </refsect2>  



<!-- ================================ SPECIFICATION  -->        
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    <refsect1 id="specification"><title>Specification</title>     
        <para>
            <imageobject>
                <imagedata fileref="pdficon_small1.gif" format="gif" />
            </imageobject>
							
            <olink uri="clCreateContextFromType">OpenCL Specification</olink>
        </para>
    </refsect1>     


<!-- ================================ ALSO SEE  -->       

    <refsect1 id="seealso"><title>Also see</title>
        <para>
<citerefentry><refentrytitle>clCreateContext</refentrytitle></citerefentry>,   <citerefentry><refentrytitle>clGetContextInfo</refentrytitle></citerefentry>,  <citerefentry><refentrytitle>clReleaseContext</refentrytitle></citerefentry>, 	 <citerefentry><refentrytitle>clRetainContext</refentrytitle></citerefentry>, 	
<citerefentry><refentrytitle>clGetContextInfo</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>

</refentry>