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<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="glGetString">
    <info>
        <copyright>
            <year>1991-2006</year>
            <holder>Silicon Graphics, Inc.</holder>
        </copyright>
        <copyright>
            <year>2010-2014</year>
            <holder>Khronos Group</holder>
        </copyright>
    </info>
    <refmeta>
        <refentrytitle>glGetString</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glGetString</refname>
        <refpurpose>return a string describing the current GL connection</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>const GLubyte* <function>glGetString</function></funcdef>
                <paramdef>GLenum <parameter>name</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
        <funcsynopsis>
            <funcprototype>
                <funcdef>const GLubyte* <function>glGetStringi</function></funcdef>
                <paramdef>GLenum <parameter>name</parameter></paramdef>
                <paramdef>GLuint <parameter>index</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 xml:id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>name</parameter></term>
            <listitem>
                <para>
                    Specifies a symbolic constant, one of
                    <constant>GL_EXTENSIONS</constant>, <constant>GL_RENDERER</constant>,
                                        <constant>GL_SHADING_LANGUAGE_VERSION</constant>, <constant>GL_VENDOR</constant>, or
                    <constant>GL_VERSION</constant>.
                    <function>glGetStringi</function> accepts only the <constant>GL_EXTENSIONS</constant> token.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>index</parameter></term>
            <listitem>
                <para>
                    For <function>glGetStringi</function>, specifies the index of the string to return.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 xml:id="description"><title>Description</title>
        <para>
            <function>glGetString</function> returns a pointer to a static string
            describing some aspect of the current GL connection.
            <parameter>name</parameter> can be one of the following:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_EXTENSIONS</constant></term>
                <listitem>
                    <para>
                        Returns the extension string supported by the implementation.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_VENDOR</constant></term>
                <listitem>
                    <para>
                        Returns the company responsible for this GL implementation.
                        This name does not change from release to release.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_RENDERER</constant></term>
                <listitem>
                    <para>
                        Returns the name of the renderer.
                        This name is typically specific to a particular configuration of a hardware
                        platform.
                        It does not change from release to release.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_VERSION</constant></term>
                <listitem>
                    <para>
                        Returns a version or release number.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term><constant>GL_SHADING_LANGUAGE_VERSION</constant></term>
                <listitem>
                    <para>
                        Returns a version or release number for the shading language.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
            <function>glGetStringi</function> returns a pointer to a static string
            indexed by <parameter>index</parameter>.
            <parameter>name</parameter> can be one of the following:
        </para>
        <variablelist>
            <varlistentry>
                <term><constant>GL_EXTENSIONS</constant></term>
                <listitem>
                    <para>
                        Returns the extension string supported by the implementation at <parameter>index</parameter>.
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
        <para>
            Strings <constant>GL_VENDOR</constant> and <constant>GL_RENDERER</constant> together uniquely specify
            a platform. They do not change from release to release and should be used
            by platform-recognition algorithms.
        </para>
        <para>
            The <constant>GL_VERSION</constant> and <constant>GL_SHADING_LANGUAGE_VERSION</constant> strings begin with a version number.
            The version number uses one
            of these forms:
        </para>
        <para>
            <emphasis>major_number.minor_number</emphasis>
            <emphasis>major_number.minor_number.release_number</emphasis>
        </para>
        <para>
            Vendor-specific information may follow the version
            number. Its format depends on the implementation, but
            a space always separates the version number and
            the vendor-specific information.
        </para>
        <para>
            All strings are null-terminated.
        </para>
    </refsect1>
    <refsect1 xml:id="notes"><title>Notes</title>
        <para>
            If an error is generated, <function>glGetString</function> returns 0.
        </para>
        <para>
            The client and server may support different versions.
            <function>glGetString</function> always returns a compatible version number.
            The release number always describes the server.
        </para>
        <para>
            There is no defined relationship between the order in which extension names appear in
            the non-indexed string and the order in which they appear in the indexed query.
        </para>
        <para>
            There is no defined relationship between any particular extension name and the index values;
            an extension name may correspond to a different index in different GL contexts and/or implementations.
        </para>
        </refsect1>
    <refsect1 xml:id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_ENUM</constant> is generated if <parameter>name</parameter> is not an accepted value.
        </para>
        <para>
            <constant>GL_INVALID_VALUE</constant> is generated by <function>glGetStringi</function> if
            <parameter>index</parameter> is outside the valid range for indexed state <parameter>name</parameter>.
        </para>
    </refsect1>
    <refsect1 xml:id="versions">
        <title>API Version Support</title>
        <informaltable>
            <tgroup cols="3" align="left">
                <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apifunchead.xml" xpointer="xpointer(/*/*)"/>
                <tbody>
                    <row>
                        <entry><function>GetString</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es20']/*)"/>
                    </row>
                    <row>
                        <entry><function>GetStringi</function></entry>
                        <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="apiversion.xml" xpointer="xpointer(/*/*[@role='es30']/*)"/>
                    </row>
                </tbody>
            </tgroup>
        </informaltable>
    </refsect1>
    <refsect1 xml:id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"/> 1991-2006 Silicon Graphics, Inc.
            Copyright <trademark class="copyright"/> 2010-2014 Khronos Group.
            This document is licensed under the SGI Free Software B License.
            For details, see
            <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://oss.sgi.com/projects/FreeB/">http://oss.sgi.com/projects/FreeB/</link>.
        </para>
    </refsect1>
</refentry>
