sdk/1.1/docs/man/clSetEventCallback.xml

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<refentry>
    <refentryinfo>clSetEventCallback
        <keywordset>
            <keyword>clSetEventCallback</keyword>
        </keywordset>
    </refentryinfo>

    <refmeta>
        <refentrytitle>       
            clSetEventCallback
        </refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2010</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="clSetEventCallback">
        <refname>     
            clSetEventCallback
        </refname> 

        <refpurpose>          
            Registers a user callback function for a specific command execution status.
        </refpurpose> 
    </refnamediv> 

    <refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>              
                    <link xlink:href="scalarDataTypes.html">cl_int</link> <function>clSetEventCallback</function>
                </funcdef>
                <paramdef><link xlink:href="abstractDataTypes.html">cl_event</link><parameter>event</parameter></paramdef>
                <paramdef>
                    <link xlink:href="scalarDataTypes.html">cl_int</link>
                    <parameter>command_exec_callback_type</parameter>
                </paramdef> 
                <paramdef><link xlink:href="scalarDataTypes.html">void</link> (CL_CALLBACK <parameter>*pfn_event_notify) 
                (<link xlink:href="abstractDataTypes.html">cl_event</link> event, <link xlink:href="scalarDataTypes.html">cl_int</link> event_command_exec_status,
                 <link xlink:href="scalarDataTypes.html">void</link> *user_data</parameter>)</paramdef>
                <paramdef><link xlink:href="scalarDataTypes.html">void</link><parameter>*user_data</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>     
    </refsynopsisdiv>


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

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

            <varlistentry>
                <term><varname>event</varname></term>
                <listitem>
                    <para>A valid event object.</para>
               </listitem>
            </varlistentry>
       
            <varlistentry>
                <term><varname>command_exec_callback_type</varname></term>
                <listitem>
                    <para> <!-- parameter description -->
                        The command execution status for which the callback is registered. The command execution callback 
                        value for which a callback can be registered is CL_COMPLETE. There is no guarantee that the callback
                        functions registered for various execution status values for an event will be called in the exact 
                        order that the execution status of a command changes.
                    </para>
                    <para>
                        The callback function registered for a <varname>command_exec_callback_type</varname> value of 
                        CL_COMPLETE will be called when the command has completed successfully or is abnormally terminated.
                    </para>
               </listitem>
            </varlistentry>
             <varlistentry>
                <term><varname>pfn_event_notify</varname></term>
                <listitem>
                    <para> <!-- parameter description -->
                        The event callback function that can be registered by the application. 
                        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. The parameters to this callback function are:
                    </para>
                    <itemizedlist mark="disc">
                        <listitem>
                            <varname>event</varname>: the event object for which the callback function is invoked.
                        </listitem>
                        <listitem>
                            <varname>event_command_exec_status</varname>: the execution status of command for which 
                            this callback function is invoked. See the table of values for 
                            <citerefentry><refentrytitle>clGetEventInfo</refentrytitle></citerefentry> 
                            <varname>param_value</varname> for the command execution status values. If the callback 
                             is 
                            called as the result of the command associated with event being abnormally terminated, an 
                            appropriate error code for the error that caused the termination will be passed to 
                            <varname>event_command_exec_status</varname> instead.
                        </listitem>
                        <listitem>
                            <varname>user_data</varname>: a pointer to user supplied data.
                        </listitem>
                    </itemizedlist>
               </listitem>
            </varlistentry>
            <varlistentry>
                <term><varname>user_data</varname></term>
                <listitem>
                    <para> <!-- parameter description -->
                        Will be passed as the <varname>user_data</varname> argument when <varname>pfn_notify</varname> 
                        is called. <varname>user_data</varname> can be NULL.
                    </para>
               </listitem>
            </varlistentry>
        </variablelist>
    </refsect1>

    
<!-- ================================ NOTES  -->        
   <refsect1 id="notes"><title>Notes</title>
        <para>
            The registered callback function will be called when the execution status of command associated with 
            <varname>event</varname> changes to the execution status specified by <varname>command_exec_status</varname>.
        </para>
        <para>
            Each call to <function>clSetEventCallback</function> registers the specified user callback function on a 
            callback stack associated with <varname>event</varname>. The order in which the registered user callback 
            functions are called is undefined.
        </para>
        <para>
            All callbacks registered for an event object must be called. All enqueued 
            callbacks shall be called before the event object is destroyed. Callbacks must 
            return promptly. The behavior of calling expensive system routines, OpenCL API 
            calls to create contexts or command-queues, or blocking OpenCL operations from 
            the following list below, in a callback is undefined.
        </para>
        <itemizedlist mark="disc">
            <listitem>
                <citerefentry><refentrytitle>clFinish</refentrytitle></citerefentry>
            </listitem>
            <listitem>
                <citerefentry><refentrytitle>clWaitForEvents</refentrytitle></citerefentry>
            </listitem>
            <listitem>
                blocking calls to <citerefentry><refentrytitle>clEnqueueReadBuffer</refentrytitle></citerefentry>, 
                <citerefentry><refentrytitle>clEnqueueReadBufferRect</refentrytitle></citerefentry>, <citerefentry><refentrytitle>clEnqueueWriteBuffer</refentrytitle></citerefentry>, and  <citerefentry><refentrytitle>clEnqueueWriteBufferRect</refentrytitle></citerefentry>
            </listitem>
            <listitem>
                blocking calls to <citerefentry><refentrytitle>clEnqueueReadImage</refentrytitle></citerefentry> and <citerefentry><refentrytitle>clEnqueueWriteImage</refentrytitle></citerefentry>
            </listitem>
            <listitem>
                blocking calls to <citerefentry><refentrytitle>clEnqueueMapBuffer</refentrytitle></citerefentry> and <citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
            </listitem>
            <listitem>
                blocking calls to <citerefentry><refentrytitle>clBuildProgram</refentrytitle></citerefentry>
            </listitem>
        </itemizedlist>
        <para>
            If an application needs to wait for completion of a routine from the above l
            ist in a callback, please use the non-blocking form of the function, and assign 
            a completion callback to it to do the remainder of your work. Note that when a 
            callback (or other code) enqueues commands to a command-queue, the commands are 
            not required to begin execution until the queue is flushed. In standard usage, 
            blocking enqueue calls serve this role by implicitly flushing the queue. Since 
            blocking calls are not permitted in callbacks, those callbacks that enqueue 
            commands on a command queue should either call 
             <citerefentry><refentrytitle>clFlush</refentrytitle></citerefentry> on the queue 
             before returning or arrange for 
             <citerefentry><refentrytitle>clFlush</refentrytitle></citerefentry> to be 
             called later on another thread.
            </para>
    </refsect1>
    

<!-- ================================ ERRORS  -->       

    <refsect1 id="errors"><title>Errors</title>
        <para>
            Returns <errorname>CL_SUCCESS</errorname> if the function is executed successfully. Otherwise, it returns 
            one of the following errors:
        </para>

        <itemizedlist mark="disc">
            <listitem>
                <errorname>CL_INVALID_EVENT</errorname> if <varname>event</varname> is not a valid event object.
            </listitem>
            <listitem>
                <errorname>CL_INVALID_VALUE</errorname> if <varname>pfn_event_notify</varname> is NULL or if 
                <varname>command_exec_callback_type</varname> is not CL_COMPLETE.
            </listitem>
            <listitem>
                <errorname>CL_OUT_OF_RESOURCES</errorname> if there is a failure to allocate resources required 
                by the OpenCL implementation on the device.
            </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>
        </itemizedlist>
    </refsect1>
    

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


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

    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry><refentrytitle>clEnqueueReadBuffer</refentrytitle></citerefentry>
        </para>
    </refsect1>-->  

<!-- ================================ COPYRIGHT  -->  
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    <refsect3 id="Copyright"><title></title>
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                <imagedata fileref="KhronosLogo.jpg" format="jpg" />
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</refentry>