Breaking into the Debugger When an Exception is Thrown

When an application throws an exception while it is being debugged, the debugger sees the exception before the program has a chance to handle it.

The debugger can allow the program to continue, or it can handle the exception.

This is usually referred to as the debugger’s first chance to handle the exception. If the debugger does not handle the exception, the program sees the exception. If the program does not handle the exception, the debugger gets a second chance to handle it.

You can control whether the debugger handles first-chance exceptions in the Exception Setting dialog box. To open the dialog box, open the debugger and select Exceptions from the Debug menu. By default, all exceptions inherit from their parent, and all are set to Continue.

This figure shows the DWRuntimeError exception has been set to Break into the debugger:

The Exception Setting dialog box shows an inheritance tree of system exceptions and allows you to select the action to take when a selected exception is thrown. In this picture, the action selected is to break into the debugger when a d w runtime error occurs.

When this exception is thrown, a dialog box lets you choose whether to open the debugger or pass the exception to the program.