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    <title>clGetEventInfo</title>
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    <div class="refentry">
      <a id="id-1"></a>
      <div class="titlepage"></div>
      <div xmlns="" class="refnamediv">
        <a xmlns="http://www.w3.org/1999/xhtml" id="clGetEventInfo"></a>
        <h1>clGetEventInfo</h1>
        <p>
            Returns information about the event object.
        </p>
      </div>
      <div class="refsynopsisdiv">
        <h2></h2>
        <div class="funcsynopsis">
          <table xmlns="" border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
            <tr valign="bottom">
              <td>
                <code xmlns="http://www.w3.org/1999/xhtml" class="funcdef">
                    <a class="link" href="scalarDataTypes.html" target="pagedisplay">cl_int</a>
                    <strong class="fsfunc">
                        clGetEventInfo
                    </strong>
                (</code>
                <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="pagedisplay">cl_event</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">event</var>, </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="enums.html#cl_event_info" target="pagedisplay">cl_event_info</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">param_name</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">size_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">param_value_size</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">void</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">*param_value</var>, </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td><a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">size_t</a> <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">*param_value_size_ret</var><code>)</code></td>
            </tr>
          </table>
        </div>
      </div>
      <div class="refsect1">
        <a id="parameters"></a>
        <h2>Parameters</h2>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term"><code class="varname"> event </code> </span>
            </dt>
            <dd>
              <p>
              Specifies the event object being queried.
            </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname">param_value </code> </span>
            </dt>
            <dd>
              <p>
               A pointer to memory where the appropriate result being queried is returned.
               If <code class="varname">param_value</code> is NULL, it is ignored.
            </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname">param_value_size </code> </span>
            </dt>
            <dd>
              <p>
              Specifies the size in bytes of memory pointed to by <code class="varname">param_value</code>.
              This size must be ≥ size of the return type as described in the table below.
            </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname">param_value_size_ret </code> </span>
            </dt>
            <dd>
              <p>
              Returns the actual size in bytes of data copied to <code class="varname">param_value</code>. If
              <code class="varname">param_value_size_ret</code> is NULL, it is ignored.
            </p>
            </dd>
            <dt>
              <span class="term"> <code class="varname">param_name </code> </span>
            </dt>
            <dd>
              <p>
              Specifies the information to query. The list of supported
              <code class="varname">param_name</code> types and the information returned in
              <code class="varname">param_value</code> by <code class="function">clGetEventInfo</code> is described
              in the table below (Table 5.22):
            </p>
              <div class="informaltable">
                <table border="1">
                  <colgroup>
                    <col align="left" class="col1" />
                    <col align="left" class="col2" />
                    <col align="left" class="col3" />
                  </colgroup>
                  <thead>
                    <tr>
                      <th align="left">cl_event_info</th>
                      <th align="left">Return Type</th>
                      <th align="left">Information returned in <code class="varname">param_value</code></th>
                    </tr>
                  </thead>
                  <tbody>
                    <tr>
                      <td align="left">
                        <code class="constant">CL_EVENT_COMMAND_QUEUE</code>
                      </td>
                      <td align="left">cl_command_queue</td>
                      <td align="left">
                      Return the command-queue associated with <code class="varname">event</code>.
                      For user event objects, a NULL value is returned.
                        If the <a class="citerefentry" href="cl_khr_gl_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_gl_sharing</span></span></a> 
                        extension is enabled, the command queue of a linked event NULL, because the event is not 
                        associated with any OpenCL command queue.
                    </td>
                    </tr>
                    <tr>
                      <td align="left">
                        <code class="constant">CL_EVENT_CONTEXT</code>
                      </td>
                      <td align="left">cl_context</td>
                      <td align="left">
                      Return the context associated with <code class="varname">event</code>.
                    </td>
                    </tr>
                    <tr>
                      <td align="left">
                        <code class="constant">CL_EVENT_COMMAND_TYPE</code>
                      </td>
                      <td align="left">cl_command_type</td>
                      <td align="left">Return the command associated with <code class="varname">event</code>.
                                    Can be one of the following values:
<div class="literallayout"><p><code class="constant">CL_COMMAND_NDRANGE_KERNEL<br />
CL_COMMAND_NATIVE_KERNEL<br />
CL_COMMAND_READ_BUFFER<br />
CL_COMMAND_WRITE_BUFFER<br />
CL_COMMAND_COPY_BUFFER<br />
CL_COMMAND_READ_IMAGE<br />
CL_COMMAND_WRITE_IMAGE<br />
CL_COMMAND_COPY_IMAGE<br />
CL_COMMAND_COPY_BUFFER_TO_IMAGE<br />
CL_COMMAND_COPY_IMAGE_TO_BUFFER<br />
CL_COMMAND_MAP_BUFFER<br />
CL_COMMAND_MAP_IMAGE<br />
CL_COMMAND_UNMAP_MEM_OBJECT<br />
CL_COMMAND_MARKER<br />
CL_COMMAND_ACQUIRE_GL_OBJECTS<br />
CL_COMMAND_RELEASE_GL_OBJECTS<br />
<br />
CL_COMMAND_READ_BUFFER_RECT<br />
CL_COMMAND_WRITE_BUFFER_RECT<br />
CL_COMMAND_COPY_BUFFER_RECT<br />
CL_COMMAND_USER<br />
CL_COMMAND_BARRIER<br />
CL_COMMAND_MIGRATE_MEM_OBJECTS<br />
CL_COMMAND_FILL_BUFFER<br />
CL_COMMAND_FILL_IMAGE<br />
<br />
CL_COMMAND_SVM_FREE<br />
CL_COMMAND_SVM_MEMCPY<br />
CL_COMMAND_SVM_MEMFILL<br />
CL_COMMAND_SVM_MAP<br />
CL_COMMAND_SVM_UNMAP<br />
<br />
CL_COMMAND_GL_FENCE_SYNC_OBJECT_KHR</code><br />
  (if <a class="citerefentry" href="cl_khr_gl_event.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_gl_event</span></span></a> <br />
is enabled, indicating that the event is <br />
associated with a GL sync object, rather than an OpenCL command)<br />
<code class="constant">CL_COMMAND_ACQUIRE_D3D10_OBJECTS_KHR</code><br />
  (if <a class="citerefentry" href="cl_khr_d3d10_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_d3d10_sharing</span></span></a> is enabled)<br />
<code class="constant">CL_COMMAND_RELEASE_D3D10_OBJECTS_KHR</code><br />
  (if <a class="citerefentry" href="cl_khr_d3d10_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_d3d10_sharing</span></span></a> is enabled)<br />
<code class="constant">CL_COMMAND_ACQUIRE_DX9_MEDIA_SURFACES_KHR</code><br />
  (if <a class="citerefentry" href="cl_khr_dx9_media_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_dx9_media_sharing</span></span></a> is enabled)<br />
<code class="constant">CL_COMMAND_RELEASE_DX9_MEDIA_SURFACES_KHR</code><br />
  (if <a class="citerefentry" href="cl_khr_dx9_media_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_dx9_media_sharing</span></span></a> is enabled)<br />
<code class="constant">CL_COMMAND_ACQUIRE_D3D11_OBJECTS_KHR</code><br />
  (if  <a class="citerefentry" href="cl_khr_d3d11_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_d3d11_sharing</span></span></a> is enabled)<br />
<code class="constant">CL_COMMAND_RELEASE_D3D11_OBJECTS_KHR</code><br />
  (if  <a class="citerefentry" href="cl_khr_d3d11_sharing.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_d3d11_sharing</span></span></a> is enabled)<br />
<code class="constant">CL_COMMAND_EGL_FENCE_SYNC_OBJECT_KHR</code><br />
  (if  <a class="citerefentry" href="cl_khr_egl_event.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_egl_event</span></span></a> is enabled)<br />
  </p></div>
                    </td>
                    </tr>
                    <tr>
                      <td align="left">
                        <code class="constant">CL_EVENT_COMMAND_ EXECUTION_STATUS</code>
                      </td>
                      <td align="left">cl_int</td>
                      <td align="left">
                      Return the execution status of the command identified by <code class="varname">event</code>.
                      The valid values are:

                      <p>
                        <code class="constant">CL_QUEUED</code> (command has been enqueued in the
                        command-queue),
                      </p>

                      <p>
                        <code class="constant">CL_SUBMITTED</code> (enqueued command has been submitted
                        by the host to the device associated with the command-queue),
                      </p>

                      <p>
                        <code class="constant">CL_RUNNING</code> (device is currently executing this
                        command),
                      </p>

                      <p>
                        <code class="constant">CL_COMPLETE</code> (the command has completed), or
                      </p>

                      <p>
                        Error code given by a negative integer value. (command was
                        abnormally terminated – this may be caused by a bad memory access
                        etc.) These error codes come from the same set of error codes that are
                        returned from the platform or runtime API calls as return values or
                        <code class="varname">errcode_ret</code> values.
                      </p>

                      <p>
                        The error code values are negative, and event state values are
                        positive. The event state values are ordered from the largest
                        value (<code class="constant">CL_QUEUED</code>) for the first or initial
                        state to the smallest value (<code class="constant">CL_COMPLETE</code> or
                        negative integer value) for the last or complete state. The value of
                        <code class="constant">CL_COMPLETE</code> and <code class="constant">CL_SUCCESS</code>
                        are the same.
                      </p>

                      <p>
                        If the <a class="citerefentry" href="cl_khr_gl_event.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_gl_event</span></span></a> 
                        extension is enabled,
                        the status of a linked event is either 
                        <code class="constant">CL_SUBMITTED</code>, indicating that 
                        the fence command associated with the sync object has 
                        not yet completed, or <code class="constant">CL_COMPLETE</code>, 
                        indicating that the fence command has completed.
                      </p>

                      <p>
                        If the <a class="citerefentry" href="cl_khr_egl_event.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_egl_event</span></span></a> 
                        extension is enabled,
                        the status of a linked event is either 
                        <code class="constant">CL_SUBMITTED</code>, indicating that 
                        the fence command associated with the sync object has 
                        not yet completed, or <code class="constant">CL_COMPLETE</code>, 
                        indicating that the fence command has completed.
                      </p>
                    </td>
                    </tr>
                    <tr>
                      <td align="left">
                        <code class="constant">CL_EVENT_REFERENCE_COUNT</code>
                      </td>
                      <td align="left">cl_uint</td>
                      <td align="left">
                      Return the <code class="varname">event</code> reference count. The reference count
                      returned should be considered immediately stale. It is unsuitable for general
                      use in applications.  This feature is provided for identifying memory leaks.
                    </td>
                    </tr>
                  </tbody>
                </table>
              </div>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
          Using <code class="function">clGetEventInfo</code> to determine if a command
          identified by <code class="varname">event</code> has finished execution
          (i.e. <code class="constant">CL_EVENT_COMMAND_EXECUTION_STATUS</code> returns
          <code class="constant">CL_COMPLETE</code>) is not a synchronization point. There are no
          guarantees that the memory objects being modified by command associated with
          <code class="varname">event</code> will be visible to other enqueued commands.
        </p>
      </div>
      <div class="refsect1">
        <a id="errors"></a>
        <h2>Errors</h2>
        <p>
            Returns <span class="errorname">CL_SUCCESS</span> if the function executed successfully.
            Otherwise, it returns one of the following errors:
        </p>
        <div class="itemizedlist">
          <ul class="itemizedlist" style="list-style-type: disc; ">
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_VALUE</span> if <code class="varname">param_name</code> is not
              valid, or if size in bytes specified by <code class="varname">param_value_size</code>
              is &lt; size of return type as described in the table above and
              <code class="varname">param_value</code> is not NULL.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_VALUE</span> if information to query given in
              <code class="varname">param_name</code> cannot be queried for event.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_EVENT</span> if <code class="varname">event</code> is not a
              valid <code class="varname">event</code> object.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_OUT_OF_RESOURCES</span> if there is a failure to allocate
              resources required by the OpenCL implementation on the device.
            </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_OUT_OF_HOST_MEMORY</span> if there is a failure to allocate
              resources required by the OpenCL implementation on the host.
            </li>
          </ul>
        </div>
      </div>
      <div class="refsect1">
        <a id="specification"></a>
        <h2>Specification</h2>
        <p>
            <img src="pdficon_small1.gif" />

            <a href="https://www.khronos.org/registry/cl/specs/opencl-2.0.pdf#page=234" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="enums.html"><span class="citerefentry"><span class="refentrytitle">enums</span></span></a>,
            <a class="citerefentry" href="clReleaseEvent.html"><span class="citerefentry"><span class="refentrytitle">clReleaseEvent</span></span></a>,
            <a class="citerefentry" href="clRetainEvent.html"><span class="citerefentry"><span class="refentrytitle">clRetainEvent</span></span></a>,
            <a class="citerefentry" href="clWaitForEvents.html"><span class="citerefentry"><span class="refentrytitle">clWaitForEvents</span></span></a>,
            <a class="citerefentry" href="cl_khr_gl_event.html"><span class="citerefentry"><span class="refentrytitle">cl_khr_gl_event</span></span></a>
        </p>
      </div>
      <div xmlns="" class="refsect3" lang="en" xml:lang="en"><a xmlns="http://www.w3.org/1999/xhtml" id="Copyright"></a><h4 xmlns="http://www.w3.org/1999/xhtml"></h4><img xmlns="http://www.w3.org/1999/xhtml" src="KhronosLogo.jpg" /><p xmlns="http://www.w3.org/1999/xhtml"></p>Copyright © 2007-2013 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
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