<?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" /><title>glGetError</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="glGetError"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetError — return error information</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">GLenum <strong class="fsfunc">glGetError</strong>(</code></td><td><code>void)</code>;</td><td> </td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
        <code class="function">glGetError</code>
        returns the value of the error flag. Each detectable error is
        assigned a numeric code and symbolic name. When an error
        occurs, the error flag is set to the appropriate error code
        value. No other errors are recorded until
        <code class="function">glGetError</code>
        is called, the error code is returned, and the flag is reset to
        <code class="constant">GL_NO_ERROR</code>. If a call to
        <code class="function">glGetError</code>
        returns <code class="constant">GL_NO_ERROR</code>,
        there has been no detectable error since the last call to
        <code class="function">glGetError</code>,
        or since the GL was initialized.</p><p>To allow for distributed implementations, there may be
        several error flags. If any single error flag has recorded an
        error, the value of that flag is returned and that flag is
        reset to <code class="constant">GL_NO_ERROR</code> when
        <code class="function">glGetError</code>
        is called. If more than one flag has recorded an error,
        <code class="function">glGetError</code>
        returns and clears an arbitrary error flag value. Thus,
        <code class="function">glGetError</code>
        should always be called in a loop, until it returns
        <code class="constant">GL_NO_ERROR</code>,
        if all error flags are to be reset.</p><p>Initially, all error flags are set to
        <code class="constant">GL_NO_ERROR</code>.</p><p>The following errors are currently defined:</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
                    <code class="constant">GL_NO_ERROR</code>
                </span></dt><dd><p>No error has been recorded. The value of this
                    symbolic constant is guaranteed to be 0.</p></dd><dt><span class="term">
                    <code class="constant">GL_INVALID_ENUM</code>
                </span></dt><dd><p>An unacceptable value is specified for an
                    enumerated argument. The offending command is ignored,
                    and has no other side effect than to set the error
                    flag.</p></dd><dt><span class="term">
                    <code class="constant">GL_INVALID_VALUE</code>
                </span></dt><dd><p>A numeric argument is out of range. The offending
                    command is ignored, and has no other side effect than to
                    set the error flag.</p></dd><dt><span class="term">
                    <code class="constant">GL_INVALID_OPERATION</code>
                </span></dt><dd><p>The specified operation is not allowed in the
                    current state. The offending command is ignored, and has
                    no other side effect than to set the error flag.</p></dd><dt><span class="term">
                    <code class="constant">GL_STACK_OVERFLOW</code>
                </span></dt><dd><p>This command would cause a stack overflow. The
                    offending command is ignored, and has no other side
                    effect than to set the error flag.</p></dd><dt><span class="term">
                    <code class="constant">GL_STACK_UNDERFLOW</code>
                </span></dt><dd><p>This command would cause a stack underflow. The
                    offending command is ignored, and has no other side
                    effect than to set the error flag.</p></dd><dt><span class="term">
                    <code class="constant">GL_OUT_OF_MEMORY</code>
                </span></dt><dd><p>There is not enough memory left to execute the
                    command. The state of the GL is undefined, except for the
                    state of the error flags, after this error is
                    recorded.</p></dd></dl></div><p>When an error flag is set, results of a GL operation are
        undefined only if <code class="constant">GL_OUT_OF_MEMORY</code>
        has occurred. In all other cases, the command generating the
        error is ignored and has no effect on the GL state or frame
        buffer contents. If the generating command returns a value, it
        returns 0. If <code class="function">glGetError</code>
        itself generates an error, it returns 0.</p></div><div class="refsect1"><a id="copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2003-2004
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></body></html>