Exception

Class Exception and its subclasses are used to indicate that an error or other problem has occurred, and may need to be handled. See Exceptions.

An Exception object carries certain information:

• The type (the exception’s class), commonly StandardError, RuntimeError, or a subclass of one or the other; see Built-In Exception Class Hierarchy.

• An optional descriptive message; see methods ::new, message.

• Optional backtrace information; see methods backtrace, backtrace_locations, set_backtrace.

• An optional cause; see method cause.

Built-In Exception Class Hierarchy

The hierarchy of built-in subclasses of class Exception:

• NoMemoryError

• ScriptError

  • LoadError

  • NotImplementedError

  • SyntaxError

• SecurityError

• SignalException

  • Interrupt

• StandardError

  • ArgumentError

    • UncaughtThrowError

  • EncodingError

  • FiberError

  • IOError

    • EOFError

  • IndexError

    • KeyError

    • StopIteration

      • ClosedQueueError

  • LocalJumpError

  • NameError

    • NoMethodError

  • RangeError

    • FloatDomainError

  • RegexpError

  • RuntimeError

    • FrozenError

  • SystemCallError

    • Errno (and its subclasses, representing system errors)

  • ThreadError

  • TypeError

  • ZeroDivisionError

• SystemExit

• SystemStackError

• fatal