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<refentry id="glGetUniformIndices">
    <refmeta>
        <refmetainfo>
            <copyright>
                <year>2010</year>
                <holder>Khronos Group</holder>
            </copyright>
        </refmetainfo>
        <refentrytitle>glGetUniformIndices</refentrytitle>
        <manvolnum>3G</manvolnum>
    </refmeta>
    <refnamediv>
        <refname>glGetUniformIndices</refname>
        <refpurpose>retrieve the index of a named uniform block</refpurpose>
    </refnamediv>
    <refsynopsisdiv><title>C Specification</title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>void <function>glGetUniformIndices</function></funcdef>
                <paramdef>GLuint <parameter>program</parameter></paramdef>
                <paramdef>GLsizei <parameter>uniformCount</parameter></paramdef>
                <paramdef>const GLchar **<parameter>uniformNames</parameter></paramdef>
                <paramdef>GLuint *<parameter>uniformIndices</parameter></paramdef>
            </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>
    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><parameter>program</parameter></term>
            <listitem>
                <para>
                    Specifies the name of a program containing uniforms whose indices to query.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>uniformCount</parameter></term>
            <listitem>
                <para>
                    Specifies the number of uniforms whose indices to query.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>uniformNames</parameter></term>
            <listitem>
                <para>
                    Specifies the address of an array of pointers to buffers containing the names of the queried uniforms.
                </para>
            </listitem>
        </varlistentry>
        <varlistentry>
            <term><parameter>uniformIndices</parameter></term>
            <listitem>
                <para>
                    Specifies the address of an array that will receive the indices of the uniforms.
                </para>
            </listitem>
        </varlistentry>
        </variablelist>
    </refsect1>
    <refsect1 id="description"><title>Description</title>
        <para>
            <function>glGetUniformIndices</function> retrieves the indices of a number of uniforms within <parameter>program</parameter>.
        </para>
        <para>
            <parameter>program</parameter> must be the name of a program object for which the command
            <citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry> must have been called in the past, although it is not required that
            <citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry> must have succeeded. The link could have failed because the number
            of active uniforms exceeded the limit.
        </para>
        <para>
            <parameter>uniformCount</parameter> indicates both the number of elements in the array of names <parameter>uniformNames</parameter> and the
            number of indices that may be written to <parameter>uniformIndices</parameter>.
        </para>
        <para>
            <parameter>uniformNames</parameter> contains a list of <parameter>uniformCount</parameter> name strings identifying the uniform names to be
            queried for indices. For each name string in <parameter>uniformNames</parameter>, the index assigned to the active uniform of that name will
            be written to the corresponding element of <parameter>uniformIndices</parameter>. If a string in <parameter>uniformNames</parameter> is not
            the name of an active uniform, the special value <constant>GL_INVALID_INDEX</constant> will be written to the corresponding element of
            <parameter>uniformIndices</parameter>.
        </para>
        <para>
            If an error occurs, nothing is written to <parameter>uniformIndices</parameter>.
        </para>
    </refsect1>
    <refsect1 id="errors"><title>Errors</title>
        <para>
            <constant>GL_INVALID_OPERATION</constant> is generated if <parameter>program</parameter> is not the name of a program object for which
            <citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry> has been called in the past.
        </para>
    </refsect1>
    <refsect1 id="notes"><title>Notes</title>
        <para>
            <function>glGetUniformIndices</function> is available only if the GL version is 3.1 or greater.
        </para>
    </refsect1>
    <refsect1 id="seealso"><title>See Also</title>
        <para>
            <citerefentry><refentrytitle>glGetActiveUniform</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glGetActiveUniformName</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>glLinkProgram</refentrytitle></citerefentry>
        </para>
    </refsect1>
    <refsect1 id="Copyright"><title>Copyright</title>
        <para>
            Copyright <trademark class="copyright"></trademark> 2010 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>
