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gdb: Exception Handling

 
 23.2.2.2 Exception Handling
 ...........................
 
 When executing the 'python' command, Python exceptions uncaught within
 the Python code are translated to calls to GDB error-reporting
 mechanism.  If the command that called 'python' does not handle the
 error, GDB will terminate it and print an error message containing the
 Python exception name, the associated value, and the Python call stack
 backtrace at the point where the exception was raised.  Example:
 
      (gdb) python print foo
      Traceback (most recent call last):
        File "<string>", line 1, in <module>
      NameError: name 'foo' is not defined
 
    GDB errors that happen in GDB commands invoked by Python code are
 converted to Python exceptions.  The type of the Python exception
 depends on the error.
 
 'gdb.error'
      This is the base class for most exceptions generated by GDB.  It is
      derived from 'RuntimeError', for compatibility with earlier
      versions of GDB.
 
      If an error occurring in GDB does not fit into some more specific
      category, then the generated exception will have this type.
 
 'gdb.MemoryError'
      This is a subclass of 'gdb.error' which is thrown when an operation
      tried to access invalid memory in the inferior.
 
 'KeyboardInterrupt'
      User interrupt (via 'C-c' or by typing 'q' at a pagination prompt)
      is translated to a Python 'KeyboardInterrupt' exception.
 
    In all cases, your exception handler will see the GDB error message
 as its value and the Python call stack backtrace at the Python statement
 closest to where the GDB error occured as the traceback.
 
    When implementing GDB commands in Python via 'gdb.Command', or
 functions via 'gdb.Function', it is useful to be able to throw an
 exception that doesn't cause a traceback to be printed.  For example,
 the user may have invoked the command incorrectly.  GDB provides a
 special exception class that can be used for this purpose.
 
 'gdb.GdbError'
      When thrown from a command or function, this exception will cause
      the command or function to fail, but the Python stack will not be
      displayed.  GDB does not throw this exception itself, but rather
      recognizes it when thrown from user Python code.  Example:
 
           (gdb) python
           >class HelloWorld (gdb.Command):
           >  """Greet the whole world."""
           >  def __init__ (self):
           >    super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_USER)
           >  def invoke (self, args, from_tty):
           >    argv = gdb.string_to_argv (args)
           >    if len (argv) != 0:
           >      raise gdb.GdbError ("hello-world takes no arguments")
           >    print "Hello, World!"
           >HelloWorld ()
           >end
           (gdb) hello-world 42
           hello-world takes no arguments
 

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