# Programming Ruby ### The Pragmatic Programmer's Guide
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class Exception |
Parent: | Object
Version: | 1.6

### Index:

exception backtrace exception message set_backtrace

Descendents of class `Exception` are used to communicate between `raise` methods and `rescue` statements in `begin/end` blocks. `Exception` objects carry information about the exception---its type (the exception's class name), an optional descriptive string, and optional traceback information.

class methods
exception | Exception.exception( [ aString ] ) -> anException
|  | Creates and returns a new exception object, optionally setting the message to aString.

instance methods
backtrace | exc.backtrace -> anArray
|  | Returns any backtrace associated with the exception. The backtrace is an array of strings, each containing either ``filename:lineNo: in `method''' or ``filename:lineNo.''

    def a
      raise "boom"
    end

    def b
      a()
    end

    begin
      b()
    rescue => detail
      print detail.backtrace.join("\n")
    end
produces:
    prog.rb:2:in `a'
    prog.rb:6:in `b'
    prog.rb:10
exception | exc.exception( [ aString ] ) -> anException or exc
|  | With no argument, returns the receiver. Otherwise, creates a new exception object of the same class as the receiver, but with a different message.
message | exc.message -> aString
|  | Returns the message associated with this exception.
set_backtrace | exc.set_backtrace( anArray ) -> anArray
|  | Sets the backtrace information associated with exc. The argument must be an array of `String` objects in the format described in `Exception#backtrace` .

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Extracted from the book "Programming Ruby - The Pragmatic Programmer's Guide"
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 http://www.opencontent.org/openpub/)).

Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder.

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.