sdk/2.1/docs/man/clGetHostTimer.xml

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<!ENTITY cl_device_type_Inc SYSTEM "cl_device_type_Inc.xml">
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<refentry>
    <refentryinfo>
        <keywordset><keyword>clGetHostTimer</keyword></keywordset>
    </refentryinfo>
    <refmeta>
        <refentrytitle>clGetHostTimer</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="clGetHostTimer">
    <refname>clGetHostTimer</refname>
    <refpurpose>Return the current value of the host clock as seen by device.</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>clGetHostTimer</function>
                </funcdef>

                <paramdef>
                    <link xlink:href="abstractDataTypes.html">cl_device_id</link>
                    <parameter>device</parameter>
                </paramdef>

                <paramdef>
                    <link xlink:href="scalarDataTypes.html">cl_ulong *</link>
                    <parameter>host_timestamp</parameter>
                </paramdef>
           </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>

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

    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><varname>device</varname></term>
            <listitem>
                <para>
                    A device returned by 
                    <citerefentry><refentrytitle>clGetDeviceIDs</refentrytitle></citerefentry>.
                </para>
            </listitem>
        </varlistentry>


        <varlistentry>
            <term><varname>host_timestamp</varname></term>
            <listitem>
                <para>
                    Will be updated with the value of the current timer in nanoseconds. The
                    resolution of the timer may be queried via 
                    <citerefentry><refentrytitle>clGetPlatformInfo</refentrytitle></citerefentry> 
                    and the flag
                    <constant>CL_PLATFORM_HOST_TIMER_RESOLUTION</constant>.
                </para>
            </listitem>
        </varlistentry>

        </variablelist>
    </refsect1>

<!-- ================================ NOTES  -->
    <refsect1 id="notes"><title>Notes</title>

    <para>
        Return the current value of the host clock as seen by 
        <varname>device</varname>. This value is in the same timebase
        as the host_timestamp returned from 
        <citerefentry><refentrytitle>clGetDeviceAndHostTimer</refentrytitle></citerefentry>. 
        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
        <citerefentry><refentrytitle>clGetDeviceAndHostTimer</refentrytitle></citerefentry> 
        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 
        <citerefentry><refentrytitle>clGetEventProfilingInfo</refentrytitle></citerefentry> 
        for an event on a device and a device
        timestamp queried from the same device will 
        always be in the same timebase.
    </para>

    </refsect1>

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

    <refsect1 id="errors"><title>Errors</title>
        <para>
            <function>clGetHostTimer</function> will return <errorname>CL_SUCCESS</errorname> 
            with a time value in <varname>host_timestamp</varname> if provided.
            Otherwise, it returns one of the following errors:
        </para>

        <itemizedlist mark="disc">
        <listitem>
            <errorname>CL_INVALID_DEVICE</errorname> if <varname>device</varname> is not
            a valid OpenCL device.
        </listitem>

        <listitem>
          <errorname>CL_INVALID_VALUE</errorname> if <varname>host_timestamp</varname> is NULL.
        </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  -->
<!-- DO NOT DELETE IN CASE AN EXAMPLE IS ADDED IN THE FUTURE -->
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    <refsect2 id="example1">
        <title>
            Example
        </title>

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            <tgroup cols="1" align="left" colsep="0" rowsep="0">
                <colspec colname="col1" colnum="1" />
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<!-- ================================ SPECIFICATION  -->
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    <refsect1 id="specification"><title>Specification</title>
        <para><imageobject><imagedata fileref="pdficon_small1.gif" format="gif" /></imageobject>
            <olink uri="clGetHostTimer">OpenCL Specification</olink>
        </para>
    </refsect1>

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

    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry><refentrytitle>clGetDeviceAndHostTimer</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>clGetPlatformInfo</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>

<!-- 29-Oct-2015, API rev. 19 -->
</refentry>