
<refentry id="glXQueryContext">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>1991-2006</year>
                <holder>Silicon Graphics, Inc.</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glXQueryContext</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glXQueryContext</refname>
        <refpurpose>query context information</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>int <function>glXQueryContext</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_FBCONFIG_ID</constant>, <constant>GLX_RENDER_TYPE</constant>, or <constant>GLX_SCREEN</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>glXQueryContext</function> sets <parameter>value</parameter> to the value of <parameter>attribute</parameter> with respect to <parameter>ctx</parameter>.
            <parameter>attribute</parameter> may be one of the following:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GLX_FBCONFIG_ID</constant></term>
                <listitem>
                    <para>
                        Returns the XID of the GLXFBConfig associated with <parameter>ctx</parameter>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GLX_RENDER_TYPE</constant></term>
                <listitem>
                    <para>
                        Returns the rendering type supported by <parameter>ctx</parameter>.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GLX_SCREEN</constant></term>
                <listitem>
                    <para>
                        Returns the screen number associated with <parameter>ctx</parameter>.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
            <constant>Success</constant> is returned unless <parameter>attribute</parameter> is not a valid GLX
            context attribute, in which case <constant>GLX_BAD_ATTRIBUTE</constant> is returned.
        </para>
        <para>
            This call may cause a round-trip to the server.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <function>glXQueryContext</function> is available only if the GLX version is 1.3 or greater.
        </para>
        <para>
            If the GLX version is 1.1 or 1.0, the GL version must be 1.0.
            If the GLX version is 1.2, then the GL version must be 1.1.
            If the GLX version is 1.3, then the GL version must be 1.2.
        </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>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glXCreateNewContext</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glXGetCurrentContext</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>
