<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "xhtml1-transitional.dtd">
<!-- saved from url=(0013)about:internet -->
<?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>glGetActiveSubroutineName - 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="glGetActiveSubroutineName"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetActiveSubroutineName — query the name of an active shader subroutine</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">glGetActiveSubroutineName</b>(</code></td><td>GLuint  </td><td><var class="pdparam">program</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">shadertype</var>, </td></tr><tr><td> </td><td>GLuint  </td><td><var class="pdparam">index</var>, </td></tr><tr><td> </td><td>GLsizei  </td><td><var class="pdparam">bufsize</var>, </td></tr><tr><td> </td><td>GLsizei * </td><td><var class="pdparam">length</var>, </td></tr><tr><td> </td><td>GLchar * </td><td><var class="pdparam">name</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>
                    Specifies the name of the program containing the subroutine.
                </p></dd><dt><span class="term"><em class="parameter"><code>shadertype</code></em></span></dt><dd><p>
                    Specifies the shader stage from which to query the subroutine name.
                </p></dd><dt><span class="term"><em class="parameter"><code>index</code></em></span></dt><dd><p>
                    Specifies the index of the shader subroutine uniform.
                </p></dd><dt><span class="term"><em class="parameter"><code>bufsize</code></em></span></dt><dd><p>
                    Specifies the size of the buffer whose address is given in <em class="parameter"><code>name</code></em>.
                </p></dd><dt><span class="term"><em class="parameter"><code>length</code></em></span></dt><dd><p>
                    Specifies the address of a variable which is to receive the length of the shader subroutine uniform name.
                </p></dd><dt><span class="term"><em class="parameter"><code>name</code></em></span></dt><dd><p>
                    Specifies the address of an array into which the name of the shader subroutine uniform will be written.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glGetActiveSubroutineName</code> queries the name of an active shader subroutine uniform from the
            program object given in <em class="parameter"><code>program</code></em>. <em class="parameter"><code>index</code></em> specifies the index of
            the shader subroutine uniform within the shader stage given by <em class="parameter"><code>stage</code></em>, and must between
            zero and the value of <code class="constant">GL_ACTIVE_SUBROUTINES</code> minus one for the shader stage.
        </p><p>
            The name of the selected subroutine is returned as a null-terminated string in <em class="parameter"><code>name</code></em>. The
            actual number of characters written into <em class="parameter"><code>name</code></em>, not including the null-terminator, is
            is returned in <em class="parameter"><code>length</code></em>. If <em class="parameter"><code>length</code></em> is <code class="constant">NULL</code>,
            no length is returned. The maximum number of characters that may be written into <em class="parameter"><code>name</code></em>,
            including the null-terminator, is given in <em class="parameter"><code>bufsize</code></em>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_VALUE</code> is generated if <em class="parameter"><code>index</code></em> is greater than or equal to
            the value of <code class="constant">GL_ACTIVE_SUBROUTINES</code>.
        </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 program object.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a href="glGetProgramStage.xml"><span class="citerefentry"><span class="refentrytitle">glGetProgramStage</span></span></a> with argument <code class="constant">GL_ACTIVE_SUBROUTINE_UNIFORM_MAX_LENGTH</code>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a href="glGetSubroutineIndex.xml"><span class="citerefentry"><span class="refentrytitle">glGetSubroutineIndex</span></span></a>,
            <a href="glGetActiveSubroutineUniform.xml"><span class="citerefentry"><span class="refentrytitle">glGetActiveSubroutineUniform</span></span></a>,
            <a href="glGetProgramStage.xml"><span class="citerefentry"><span class="refentrytitle">glGetProgramStage</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>© 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.
            <a href="http://opencontent.org/openpub/" target="_top">http://opencontent.org/openpub/</a>.
        </p></div></div></body></html>
