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<refentry id="glWaitSync">
    <refentryinfo>
        <copyright>
            <year>2010-2013</year>
            <holder>Khronos Group</holder>
        </copyright>
    </refentryinfo>
    <refmeta>
        <refentrytitle>glWaitSync</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glWaitSync</refname>
        <refpurpose>instruct the GL server to block until the specified sync object becomes signaled</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glWaitSync</function></funcdef>
                <paramdef>GLsync <parameter>sync</parameter></paramdef>
                <paramdef>GLbitfield <parameter>flags</parameter></paramdef>
                <paramdef>GLuint64 <parameter>timeout</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>sync</parameter></term>
            <listitem>
                <para>
                    Specifies the sync object whose status to wait on.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>flags</parameter></term>
            <listitem>
                <para>
                    A bitfield controlling the command flushing behavior. <parameter>flags</parameter> may be zero.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>timeout</parameter></term>
            <listitem>
                <para>
                    Specifies the timeout that the server should wait before continuing. <parameter>timeout</parameter> must be <constant>GL_TIMEOUT_IGNORED</constant>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>glWaitSync</function> causes the GL server to block and wait until <parameter>sync</parameter> becomes signaled. <parameter>sync</parameter>
            is the name of an existing sync object upon which to wait. <parameter>flags</parameter> and <parameter>timeout</parameter> are currently not used and
            must be set to zero and the special value <constant>GL_TIMEOUT_IGNORED</constant>, respectively<footnote><para><parameter>flags</parameter> and
            <parameter>timeout</parameter> are placeholders for anticipated future extensions of sync object capabilities. They must have these reserved values in
            order that existing code calling <function>glWaitSync</function> operate properly in the presence of such extensions.</para></footnote>. <function>glWaitSync</function> will always wait no longer than an implementation-dependent timeout. The
            duration of this timeout in nanoseconds may be queried by calling <citerefentry><refentrytitle>glGet</refentrytitle></citerefentry> with the
            parameter <constant>GL_MAX_SERVER_WAIT_TIMEOUT</constant>. There is currently no way to determine whether <function>glWaitSync</function> unblocked
            because the timeout expired or because the sync object being waited on was signaled.
        </para>
        <para>
            If an error occurs, <function>glWaitSync</function> does not cause the GL server to block.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <function>glWaitSync</function> is available only if the GL version is 3.2 or higher.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>sync</parameter> is not the name of a sync object.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>flags</parameter> is not zero.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated if <parameter>timeout</parameter> is not <constant>GL_TIMEOUT_IGNORED</constant>.
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glFenceSync</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glClientWaitSync</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 2010-2013 Khronos Group.
            This material may be distributed subject to the terms and conditions set forth in
            the Open Publication License, v 1.0, 8 June 1999.
            <ulink url="http://opencontent.org/openpub/">http://opencontent.org/openpub/</ulink>.
        </para>
    </refsect1>
</refentry>
