sdk/2.0/docs/man/clSetEventCallback.xml

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

    <refmeta>
        <refentrytitle>
            clSetEventCallback
        </refentrytitle>

        <refmiscinfo>
            <copyright>
                <year>2007-2013</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="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>
                      Specifies the command execution status for which
                      the callback is registered. The command execution callback values for
                      which a callback can be registered are <constant>CL_SUBMITTED</constant>,
                      <constant>CL_RUNNING</constant>, or <constant>CL_COMPLETE</constant>.
                      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. Furthermore, it should
                      be noted that receiving a call back for an event with a status other than
                      <constant>CL_COMPLETE</constant>, in no way implies that the memory model
                      or execution model as defined by the OpenCL specification has changed. For
                      example, it is not valid to assume that a corresponding memory transfer has
                      completed unless the event is in a state <constant>CL_COMPLETE</constant>.
                    </para>

                    <para>
                      The callback function registered for a
                      <varname>command_exec_callback_type</varname> value of
                      <constant>CL_COMPLETE</constant> 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>
                      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> is the event object for which the 
                            callback function is invoked.
                        </listitem>

                        <listitem>
                          <varname>event_command_exec_status</varname> represents the
                          execution status of command for which this callback function is
                          invoked. See the table of values for <varname>param_value</varname> for
                          <citerefentry><refentrytitle>clGetEventInfo</refentrytitle></citerefentry>
                          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> is a pointer to user supplied data.
                        </listitem>
                    </itemizedlist>
               </listitem>
            </varlistentry>

            <varlistentry>
                <term><varname>user_data</varname></term>
                <listitem>
                    <para>
                      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 an execution status equal to or
          past the 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>,
              <citerefentry><refentrytitle>clCompileProgram</refentrytitle></citerefentry>,
              or <citerefentry><refentrytitle>clLinkProgram</refentrytitle></citerefentry>.
            </listitem>

            <listitem>
              blocking calls to
              <citerefentry><refentrytitle>clEnqueueSVMMemcpy</refentrytitle></citerefentry>,
              or <citerefentry><refentrytitle>clEnqueueSVMMap</refentrytitle></citerefentry>.
            </listitem>
        </itemizedlist>

        <para>
          If an application needs to wait for completion of a routine from the above list 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 
                <constant>CL_SUBMITTED</constant>, <constant>CL_RUNNING</constant> or
                <constant>CL_COMPLETE</constant>.
            </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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        <title>
            Example
        </title>

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                <colspec colname="col1" colnum="1" />
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                        </entry>
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        </informaltable>
    </refsect2>
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<!-- ================================ SPECIFICATION  -->
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    <refsect1 id="specification"><title>Specification</title>
        <para>
            <imageobject>
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            </imageobject>

            <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>
        <imageobject>
                <imagedata fileref="KhronosLogo.jpg" format="jpg" />
        </imageobject>
        <para />
    </refsect3>

<!-- 24-Dec-2013, rev. 19 -->
</refentry>