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    <title>clGetHostTimer</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="clGetHostTimer"></a>
        <h1>clGetHostTimer</h1>
        <p>Return the current value of the host clock as seen by device.</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">clGetHostTimer</strong>
                (</code>
                <td>
                    <a xmlns="http://www.w3.org/1999/xhtml" class="link" href="abstractDataTypes.html" target="pagedisplay">cl_device_id</a>
                     <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">device</var>
                , </td>
              </td>
            </tr>
            <tr valign="top">
              <td> </td>
              <td>
                    <a xmlns="http://www.w3.org/1999/xhtml" class="link" href="scalarDataTypes.html" target="pagedisplay">cl_ulong *</a>
                     <var xmlns="http://www.w3.org/1999/xhtml" class="pdparam">host_timestamp</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">device</code>
              </span>
            </dt>
            <dd>
              <p>
                    A device returned by 
                    <a class="citerefentry" href="clGetDeviceIDs.html"><span class="citerefentry"><span class="refentrytitle">clGetDeviceIDs</span></span></a>.
                </p>
            </dd>
            <dt>
              <span class="term">
                <code class="varname">host_timestamp</code>
              </span>
            </dt>
            <dd>
              <p>
                    Will be updated with the value of the current timer in nanoseconds. The
                    resolution of the timer may be queried via 
                    <a class="citerefentry" href="clGetPlatformInfo.html"><span class="citerefentry"><span class="refentrytitle">clGetPlatformInfo</span></span></a> 
                    and the flag
                    <code class="constant">CL_PLATFORM_HOST_TIMER_RESOLUTION</code>.
                </p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1">
        <a id="notes"></a>
        <h2>Notes</h2>
        <p>
        Return the current value of the host clock as seen by 
        <code class="varname">device</code>. This value is in the same timebase
        as the host_timestamp returned from 
        <a class="citerefentry" href="clGetDeviceAndHostTimer.html"><span class="citerefentry"><span class="refentrytitle">clGetDeviceAndHostTimer</span></span></a>. 
        The implementation will
        return with as low a latency as possible to 
        allow a correlation with a subsequent application
        sampled time. The host timestamp and device 
        timestamp returned by this function and
        <a class="citerefentry" href="clGetDeviceAndHostTimer.html"><span class="citerefentry"><span class="refentrytitle">clGetDeviceAndHostTimer</span></span></a> 
        each have an implementation defined timebase. The timestamps
        will always be in their respective timebases 
        regardless of which query function is used. The
        timestamp returned from 
        <a class="citerefentry" href="clGetEventProfilingInfo.html"><span class="citerefentry"><span class="refentrytitle">clGetEventProfilingInfo</span></span></a> 
        for an event on a device and a device
        timestamp queried from the same device will 
        always be in the same timebase.
    </p>
      </div>
      <div class="refsect1">
        <a id="errors"></a>
        <h2>Errors</h2>
        <p>
            <code class="function">clGetHostTimer</code> will return <span class="errorname">CL_SUCCESS</span> 
            with a time value in <code class="varname">host_timestamp</code> if provided.
            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_DEVICE</span> if <code class="varname">device</code> is not
            a valid OpenCL device.
        </li>
            <li class="listitem" style="list-style-type: disc"><span class="errorname">CL_INVALID_VALUE</span> if <code class="varname">host_timestamp</code> is NULL.
        </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-2.1.pdf#page=83" target="OpenCL Spec">OpenCL Specification</a>
        </p>
      </div>
      <div class="refsect1">
        <a id="seealso"></a>
        <h2>Also see</h2>
        <p>
            <a class="citerefentry" href="clGetDeviceAndHostTimer.html"><span class="citerefentry"><span class="refentrytitle">clGetDeviceAndHostTimer</span></span></a>,
            <a class="citerefentry" href="clGetPlatformInfo.html"><span class="citerefentry"><span class="refentrytitle">clGetPlatformInfo</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 © 2007-2015 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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