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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glGetProgramInterface - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glGetProgramInterface"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetProgramInterface — query a property of an interface in a program</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0"><tr><td><code class="funcdef">void <b class="fsfunc">glGetProgramInterfaceiv</b>(</code></td><td>GLuint  </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">programInterface</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">pname</var>, </td></tr><tr><td> </td><td>GLint *  </td><td><var class="pdparam">params</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>program</code></em></span></dt><dd><p>
                    The name of a program object whose interface to query.
                </p></dd><dt><span class="term"><em class="parameter"><code>programInterface</code></em></span></dt><dd><p>
                    A token identifying the interface within <em class="parameter"><code>program</code></em> to query.
                </p></dd><dt><span class="term"><em class="parameter"><code>pname</code></em></span></dt><dd><p>
                    The name of the parameter within <em class="parameter"><code>programInterface</code></em> to query.
                </p></dd><dt><span class="term"><em class="parameter"><code>params</code></em></span></dt><dd><p>
                    The address of a variable to retrieve the value of <em class="parameter"><code>pname</code></em> for the program interface.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glGetProgramInterfaceiv</code> queries the property of the interface identifed
            by <em class="parameter"><code>programInterface</code></em> in <em class="parameter"><code>program</code></em>, the property name of
            which is given by <em class="parameter"><code>pname</code></em>.
        </p><p>
            <em class="parameter"><code>program</code></em> must be the name of an existing program object. <em class="parameter"><code>programInterface</code></em>
            is the name of the interface within <em class="parameter"><code>program</code></em> to query and must be one of the following
            values:
        </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_UNIFORM</code></span></dt><dd><p>
                        The query is targeted at the set of active uniforms within <em class="parameter"><code>program</code></em>.
                    </p></dd><dt><span class="term"><code class="constant">GL_UNIFORM_BLOCK</code></span></dt><dd><p>
                        The query is targeted at the set of active uniform blocks within <em class="parameter"><code>program</code></em>.
                    </p></dd><dt><span class="term"><code class="constant">GL_ATOMIC_COUNTER_BUFFER</code></span></dt><dd><p>
                        The query is targeted at the set of active atomic counter buffer binding points within <em class="parameter"><code>program</code></em>.
                    </p></dd><dt><span class="term"><code class="constant">GL_PROGRAM_INPUT</code></span></dt><dd><p>
                        The query is targeted at the set of active input variables used by the first shader stage of <em class="parameter"><code>program</code></em>.
                        If <em class="parameter"><code>program</code></em> contains multiple shader stages then input variables from any stage other than the first
                        will not be enumerated.
                    </p></dd><dt><span class="term"><code class="constant">GL_PROGRAM_OUTPUT</code></span></dt><dd><p>
                        The query is targeted at the set of active output variables produced by the last shader stage of <em class="parameter"><code>program</code></em>.
                        If <em class="parameter"><code>program</code></em> contains multiple shader stages then output variables from any stage other than the last
                        will not be enumerated.
                    </p></dd><dt><span class="term"><code class="constant">GL_VERTEX_SUBROUTINE</code>, </span><span class="term"><code class="constant">GL_TESS_CONTROL_SUBROUTINE</code>, </span><span class="term"><code class="constant">GL_TESS_EVALUATION_SUBROUTINE</code>, </span><span class="term"><code class="constant">GL_GEOMETRY_SUBROUTINE</code>, </span><span class="term"><code class="constant">GL_FRAGMENT_SUBROUTINE</code>, </span><span class="term"><code class="constant">GL_COMPUTE_SUBROUTINE</code></span></dt><dd><p>
                        The query is targeted at the set of active subroutines for the vertex, tessellation control, tessellation evaluation,
                        geometry, fragment and compute shader stages of <em class="parameter"><code>program</code></em>, respectively.
                    </p></dd><dt><span class="term"><code class="constant">GL_VERTEX_SUBROUTINE_UNIFORM</code>, </span><span class="term"><code class="constant">GL_TESS_CONTROL_SUBROUTINE_UNIFORM</code>, </span><span class="term"><code class="constant">GL_TESS_EVALUATION_SUBROUTINE_UNIFORM</code>, </span><span class="term"><code class="constant">GL_GEOMETRY_SUBROUTINE_UNIFORM</code>, </span><span class="term"><code class="constant">GL_FRAGMENT_SUBROUTINE_UNIFORM</code>, </span><span class="term"><code class="constant">GL_COMPUTE_SUBROUTINE_UNIFORM</code></span></dt><dd><p>
                        The query is targeted at the set of active subroutine uniform variables used by the vertex, tessellation control, tessellation evaluation,
                        geometry, fragment and compute shader stages of <em class="parameter"><code>program</code></em>, respectively.
                    </p></dd><dt><span class="term"><code class="constant">GL_TRANSFORM_FEEDBACK_VARYING</code></span></dt><dd><p>
                        The query is targeted at the set of output variables from the last non-fragment stage of <em class="parameter"><code>program</code></em> that would be
                        captured if transform feedback were active.
                    </p></dd><dt><span class="term"><code class="constant">GL_BUFFER_VARIABLE</code></span></dt><dd><p>
                        The query is targeted at the set of active buffer variables used by <em class="parameter"><code>program</code></em>.
                    </p></dd><dt><span class="term"><code class="constant">GL_SHADER_STORAGE_BLOCK</code></span></dt><dd><p>
                        The query is targeted at the set of active shader storage blocks used by <em class="parameter"><code>program</code></em>.
                    </p></dd></dl></div><p>
            <em class="parameter"><code>pname</code></em> identifies the property of <em class="parameter"><code>programInterface</code></em>
            to return in <em class="parameter"><code>params</code></em>.
        </p><p>
            If <em class="parameter"><code>pname</code></em> is <code class="constant">GL_ACTIVE_RESOURCES</code>, the value returned is the number of
            resources in the active resource list for <em class="parameter"><code>programInterface</code></em>.  If the list
            of active resources for <em class="parameter"><code>programInterface</code></em> is empty, zero is returned.
        </p><p>
            If <em class="parameter"><code>pname</code></em> is <code class="constant">GL_MAX_NAME_LENGTH</code>, the value returned is the length of the
            longest active name string for an active resource in <em class="parameter"><code>programInterface</code></em>.
            This length includes an extra character for the null terminator.  If the
            list of active resources for <em class="parameter"><code>programInterface</code></em> is empty, zero is
            returned.  It is an error to specify <code class="constant">GL_MAX_NAME_LENGTH</code> when <em class="parameter"><code>programInterface</code></em>
            is <code class="constant">GL_ATOMIC_COUNTER_BUFFER</code>, as active atomic counter buffer resources are
            not assigned name strings.
        </p><p>
            If <em class="parameter"><code>pname</code></em> is <code class="constant">GL_MAX_NUM_ACTIVE_VARIABLES</code>, the value returned is the number
            of active variables belonging to the interface block or atomic counter
            buffer resource in <em class="parameter"><code>programInterface</code></em> with the most active variables.  If
            the list of active resources for <em class="parameter"><code>programInterface</code></em> is empty, zero is
            returned.  When <em class="parameter"><code>pname</code></em> is <code class="constant">GL_MAX_NUM_ACTIVE_VARIABLES</code>, <em class="parameter"><code>programInterface</code></em>
            must be <code class="constant">GL_UNIFORM_BLOCK</code>, <code class="constant">GL_ATOMIC_COUNTER_BUFFER</code>, or <code class="constant">GL_SHADER_STORAGE_BLOCK</code>.
        </p><p>
            If <em class="parameter"><code>pname</code></em> is <code class="constant">GL_MAX_NUM_COMPATIBLE_SUBROUTINES</code>, the value returned is the
            number of compatible subroutines belonging to the active subroutine
            uniform in <em class="parameter"><code>programInterface</code></em> with the most compatible subroutines.  If
            the list of active resources for <em class="parameter"><code>programInterface</code></em> is empty, zero is
            returned. When <em class="parameter"><code>pname</code></em> is <code class="constant">GL_MAX_NUM_COMPATIBLE_SUBROUTINES</code>,
            <em class="parameter"><code>programInterface</code></em> must be one of <code class="constant">GL_VERTEX_SUBROUTINE_UNIFORM</code>,
            <code class="constant">GL_TESS_CONTROL_SUBROUTINE_UNIFORM</code>, <code class="constant">GL_TESS_EVALUATION_SUBROUTINE_UNIFORM</code>,
            <code class="constant">GL_GEOMETRY_SUBROUTINE_UNIFORM</code>, <code class="constant">GL_FRAGMENT_SUBROUTINE_UNIFORM</code>, or
            <code class="constant">GL_COMPUTE_SUBROUTINE_UNIFORM</code>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>identifier</code></em>
            is not one of the accepted object types.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>program</code></em>
            is not the name of an existing sync object.
        </p><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>bufSize</code></em> is
            zero.
        </p><p>
            If not NULL, <em class="parameter"><code>length</code></em> and <em class="parameter"><code>label</code></em> should be addresses
            to which the client has write access, otherwise undefined behavior, including process termination
            may occur.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_MAX_LABEL_LENGTH</code>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a href="glPushDebugGroup.xml"><span class="citerefentry"><span class="refentrytitle">glPushDebugGroup</span></span></a>,
            <a href="glPopDebugGroup.xml"><span class="citerefentry"><span class="refentrytitle">glPopDebugGroup</span></span></a>,
            <a href="glObjectLabel.xml"><span class="citerefentry"><span class="refentrytitle">glObjectLabel</span></span></a>,
            <a href="glGetObjectLabel.xml"><span class="citerefentry"><span class="refentrytitle">glGetObjectLabel</span></span></a>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2012 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.
            <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p></div></div></body></html>
