<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <title>Programming Ruby: The Pragmatic Programmer's Guide</title> <link rel="StyleSheet" href="pr_style.css" type="text/css" media="screen"> </head> <body bgcolor="white"> <table bgcolor="#c09090" cellpadding="3" border="0" cellspacing="0" width="100%"> <tr> <td colspan="3"> <table bgcolor="#701a1a" cellpadding="20" width="100%"> <tr> <td width="6in"> <h1 class="header">Programming Ruby</h1> <h3 class="subheader">The Pragmatic Programmer's Guide</h3> </td> </tr> </table> </td> </tr> <tr> <td width="33%" align="left"> <a class="subheader" href="ref_c_dir.html">Previous <</a> </td> <td width="33%" align="center" valign="middle"> <a class="subheader" href="builtins.html">Contents ^</a> <br> </td> <td width="33%" align="right"> <a class="subheader" href="ref_c_falseclass.html">Next ></a> <br> </td> </tr> </table> <!-- Copyright (c) 2001 by Addison Wesley Longman, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). <P></P> Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. <P></P> Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder. --> <table> <tr> <td height="20"><img src="dot.gif" width="1" height="20"></td> </tr> </table> <table border="0" width="100%" bgcolor="660066" cellpadding="10"> <tr> <td valign="center"> <font color="white" size="7">class Exception</font> </td> <td> <table border="0"> <tr> <td> <font color="white"> Parent: </font> </td> <td> <font color="white">Object</font> </td> </tr> <tr> <td> <font color="white"> Version: </font> </td> <td> <font color="white"> 1.6 </font> </td> </tr> </table> </td> </tr> </table> <p></p> <H3>Index:</H3> <a href="#Exception.exception">exception</a> <i> <a href="#Exception.backtrace">backtrace</a> </i> <i> <a href="#Exception.exception">exception</a> </i> <i> <a href="#Exception.message">message</a> </i> <i> <a href="#Exception.set_backtrace">set_backtrace</a> </i> <p></p> <hr> <P></P> Descendents of class <code>Exception</code> are used to communicate between <code>raise</code> methods and <code>rescue</code> statements in <code>begin/end</code> blocks. <code>Exception</code> objects carry information about the exception---its type (the exception's class name), an optional descriptive string, and optional traceback information. <P></P> <table border="0" width="100%" cellpadding="10"> <tr> <td valign="center" colspan="2" bgcolor="990066"> <font color="white" size="6">class methods </font> </td> </tr> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="Exception.exception">exception</a> </b> </font> </td> <td bgcolor="#ffaaaa"> Exception.exception( <i>[</i> <i>aString</i> <i>]</i> ) -> <i>anException</i> </td> </tr> <td></td> <td> <P></P> Creates and returns a new exception object, optionally setting the message to <i>aString</i>. <P></P> </td> </table> <P></P> <table border="0" width="100%" cellpadding="10"> <tr> <td valign="center" colspan="2" bgcolor="990066"> <font color="white" size="6">instance methods </font> </td> </tr> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="Exception.backtrace">backtrace</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <i>exc</i>.backtrace -> <i>anArray</i> </td> </tr> <td></td> <td> <P></P> Returns any backtrace associated with the exception. The backtrace is an array of strings, each containing either ``filename:lineNo: in `method''' or ``filename:lineNo.'' <P></P> <table class="codebox" cellspacing="0" border="0" cellpadding="3" width="400"> <tr> <td> <pre> def a raise "boom" end <P></P> def b a() end <P></P> begin b() rescue => detail print detail.backtrace.join("\n") end </pre> </td> </tr> </table> <em>produces:</em> <table class="codebox" cellspacing="0" border="0" cellpadding="3" width="400"> <tr> <td> <pre> prog.rb:2:in `a' prog.rb:6:in `b' prog.rb:10 </pre> </td> </tr> </table> <P></P> </td> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="Exception.exception">exception</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <i>exc</i>.exception( <i>[</i> <i>aString</i> <i>]</i> ) -> <i>anException</i> or <i>exc</i> </td> </tr> <td></td> <td> <P></P> With no argument, returns the receiver. Otherwise, creates a new exception object of the same class as the receiver, but with a different message. <P></P> </td> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="Exception.message">message</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <i>exc</i>.message -> <i>aString</i> </td> </tr> <td></td> <td> <P></P> Returns the message associated with this exception. <P></P> </td> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="Exception.set_backtrace">set_backtrace</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <i>exc</i>.set_backtrace( <i>anArray</i> ) -> <i>anArray</i> </td> </tr> <td></td> <td> <P></P> Sets the backtrace information associated with <i>exc</i>. The argument must be an array of <code>String</code> objects in the format described in <a href="ref_c_exception.html#Exception.backtrace"> <code>Exception#backtrace</code> </a>. <P></P> </td> </table> <P></P> <p></p> <hr> <table bgcolor="#a03030" cellpadding="10" border="0" cellspacing="0"> <tr> <td width="33%" align="left"> <a class="subheader" href="ref_c_dir.html">Previous <</a> </td> <td width="33%" align="center" valign="middle"> <a class="subheader" href="builtins.html">Contents ^</a> <br> </td> <td width="33%" align="right"> <a class="subheader" href="ref_c_falseclass.html">Next ></a> <br> </td> </tr> </table> <p></p> <font size="-1">Extracted from the book "Programming Ruby - The Pragmatic Programmer's Guide"</font> <br> <font size="-3"> Copyright © 2001 by Addison Wesley Longman, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at <a href="http://www.opencontent.org/openpub/">http://www.opencontent.org/openpub/</a>)). <p></p> Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. <p></p> Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder. <br> </font> </body> </html>