
<refentry id="glXQueryContextInfoEXT">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glXQueryContextInfoEXT</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glXQueryContextInfoEXT</refname>
        <refpurpose>query context information</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>int <function>glXQueryContextInfoEXT</function></funcdef>
                <paramdef>Display * <parameter>dpy</parameter></paramdef>
                <paramdef>GLXContext <parameter>ctx</parameter></paramdef>
                <paramdef>int <parameter>attribute</parameter></paramdef>
                <paramdef>int * <parameter>value</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <!-- eqn: ignoring delim $$ -->
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>dpy</parameter></term>
            <listitem>
                <para>
                    Specifies the connection to the X server.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>ctx</parameter></term>
            <listitem>
                <para>
                    Specifies a GLX rendering context.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>attribute</parameter></term>
            <listitem>
                <para>
                    Specifies that a context parameter should be retrieved.  Must be one of
                    <constant>GLX_SHARED_CONTEXT_EXT</constant>, <constant>GLX_VISUAL_ID_EXT</constant>, or <constant>GLX_SCREEN_EXT</constant>.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>value</parameter></term>
            <listitem>
                <para>
                    Contains the return value for <parameter>attribute</parameter>.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>glXQueryContextInfoEXT</function> sets <parameter>value</parameter> to the value of <parameter>attribute</parameter> with respect to <parameter>ctx</parameter>.
            <function>glXQueryContextInfoEXT</function> returns an error code if it fails for any reason. Otherwise,
            <constant>Success</constant> is returned.
        </para>
        <para>
            <parameter>attribute</parameter> may be one of the following:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GLX_SHARED_CONTEXT_EXT</constant></term>
                <listitem>
                    <para>
                        Returns the XID of the share list context associated with <parameter>ctx</parameter> at its
                        creation.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GLX_VISUAL_ID_EXT</constant></term>
                <listitem>
                    <para>
                        Returns the XID of the GLX Visual associated with <parameter>ctx</parameter>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GLX_SCREEN_EXT</constant></term>
                <listitem>
                    <para>
                        Returns the screen number associated with <parameter>ctx</parameter>.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
            This call may cause a round-trip to the server.
        </para>
        <para>
            <function>glXQueryContextInfoEXT</function> is part of the <code>EXT_import_context</code> extension,
            not part of the core GLX command set. If _glxextstring(EXT_import_context)
            is included in the string returned by <citerefentry><refentrytitle>glXQueryExtensionsString</refentrytitle></citerefentry>,
            when called with argument <constant>GLX_EXTENSIONS</constant>,
            extension <code>EXT_import_context</code> is supported.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GLXBadContext</constant> is generated if <parameter>ctx</parameter> does not
            refer to a valid context.
        </para>
        <para>
            <constant>GLX_BAD_ATTRIBUTE</constant> is returned if <parameter>attribute</parameter> is not a valid GLX
            context attribute.
        </para>
        <para>
            fred <constant>GLX_BAD_CONTEXT</constant> is returned if <parameter>attribute</parameter> is not a valid context.
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glXCreateContext</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glXQueryVersion</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glXQueryExtensionsString</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <ulink url="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</ulink>.
        </para>
    </refsect1>
</refentry>
