<div class="refentry"><a id="glGetAttribLocation"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetAttribLocation — return the location of an attribute variable</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table class="funcprototype-table" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">GLint <strong class="fsfunc">glGetAttribLocation</strong>(</code></td><td>GLuint <var class="pdparam">program</var>, </td></tr><tr><td> </td><td>const GLchar *<var class="pdparam">name</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>program</code></em></span></dt><dd><p>Specifies the program object to be

queried.</p></dd><dt><span class="term"><em class="parameter"><code>name</code></em></span></dt><dd><p>Points to a null terminated string containing

the name of the attribute variable whose location is

to be queried.</p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p><code class="function">glGetAttribLocation</code> queries the

previously linked program object specified by

<em class="parameter"><code>program</code></em> for the attribute variable

specified by <em class="parameter"><code>name</code></em> and returns the index

of the generic vertex attribute that is bound to that attribute

variable. If <em class="parameter"><code>name</code></em> is a matrix attribute

variable, the index of the first column of the matrix is

returned. If the named attribute variable is not an active

attribute in the specified program object or if

<em class="parameter"><code>name</code></em> starts with the reserved prefix

"gl_", a value of -1 is returned.</p><p>The association between an attribute variable name and a

generic attribute index can be specified at any time by calling

<a class="citerefentry" href="glBindAttribLocation"><span class="citerefentry"><span class="refentrytitle">glBindAttribLocation</span></span></a>.

Attribute bindings do not go into effect until

<a class="citerefentry" href="glLinkProgram"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>

is called. After a program object has been linked successfully,

the index values for attribute variables remain fixed until the

next link command occurs. The attribute values can only be

queried after a link if the link was successful.

<code class="function">glGetAttribLocation</code> returns the binding

that actually went into effect the last time

<a class="citerefentry" href="glLinkProgram"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>

was called for the specified program object. Attribute bindings

that have been specified since the last link operation are not

returned by <code class="function">glGetAttribLocation</code>.</p></div><div class="refsect1"><a id="errors"></a><h2>Errors</h2><p><code class="constant">GL_INVALID_OPERATION</code> is generated if

<em class="parameter"><code>program</code></em> is not a value generated by

OpenGL.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if

<em class="parameter"><code>program</code></em> is not a program object.</p><p><code class="constant">GL_INVALID_OPERATION</code> is generated if

<em class="parameter"><code>program</code></em> has not been successfully

linked.</p></div><div class="refsect1"><a id="associatedgets"></a><h2>Associated Gets</h2><p><a class="citerefentry" href="glGetActiveAttrib"><span class="citerefentry"><span class="refentrytitle">glGetActiveAttrib</span></span></a>

with argument <em class="parameter"><code>program</code></em> and the index of an

active attribute</p><p><a class="citerefentry" href="glIsProgram"><span class="citerefentry"><span class="refentrytitle">glIsProgram</span></span></a></p></div>

{$pipelinestall}{$examples}

<div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p><a class="citerefentry" href="glBindAttribLocation"><span class="citerefentry"><span class="refentrytitle">glBindAttribLocation</span></span></a>,

<a class="citerefentry" href="glLinkProgram"><span class="citerefentry"><span class="refentrytitle">glLinkProgram</span></span></a>,

<a class="citerefentry" href="glVertexAttrib"><span class="citerefentry"><span class="refentrytitle">glVertexAttrib</span></span></a>,

<a class="citerefentry" href="glVertexAttribPointer"><span class="citerefentry"><span class="refentrytitle">glVertexAttribPointer</span></span></a></p></div><div class="refsect1"><div id="Copyright"><h2>Copyright</h2><p>

Copyright © 2003-2005 3Dlabs Inc. Ltd.

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 class="ulink" href="https://opencontent.org/openpub/" target="_top">https://opencontent.org/openpub/</a>.

</p></div></div></div>