Supported Event Types

Visual Studio debugging currently supports the following event types:

• Asynchronous events

  Notify the session debug manager (SDM) and IDE that the state of the application being debugged is changing. These events are processed at the leisure of the SDM and the IDE. No reply is sent to the debug engine (DE) once the event is processed. The IDebugOutputStringEvent2 and IDebugMessageEvent2 interfaces are examples of asynchronous events.

• Synchronous events

  Notify the SDM and IDE that the state of the application being debugged is changing. The only difference between these events and asynchronous events is that a reply is sent by means of the IDebugEngine2::ContinueFromSynchronousEvent method.

  Sending a synchronous event is useful if you need your DE to continue processing after the IDE receives and processes the event.

• Synchronous stopping events, or stopping events

  Notify the SDM and the IDE that the application being debugged has stopped executing code. When you send a stopping event by means of the method IDebugEventCallback2::Event, the IDebugThread2 parameter is required. Stopping events are continued by a call to the one of the following methods:

  • IDebugProgram2::Execute

  • IDebugProgram2::Step

  • IDebugProgram2::Continue

  The interfaces IDebugBreakpointEvent2 and IDebugExceptionEvent2 are examples of stopping events.

  Note

  Asynchronous stopping events are not supported. It is an error to send an asynchronous stopping event.

Discussion

The actual implementation of events depends on the design of your DE. The type of each event sent is determined by its attributes, which are set when you design the DE. For example, one DE may send an IDebugProgramCreateEvent2 as an asynchronous event, while another may send it as a stopping event.

The following table specifies which program and thread parameters are required for which events, as well as event types. Any event can be synchronous. No event needs to be synchronous.

Note

The IDebugEngine2 interface is required for all events.

Event	IDebugProgram2	IDebugThread2	Stopping Events
IDebugActivateDocumentEvent2	Allowed, but not required	Allowed, but not required	No
IDebugBreakEvent2	Required	Required	Yes
IDebugBreakpointBoundEvent2	Allowed, but not required	Allowed, but not required	No
IDebugBreakpointErrorEvent2	Allowed, but not required	Allowed, but not required	No
IDebugBreakpointUnboundEvent2	Allowed, but not required	Allowed, but not required	No
IDebugBreakpointEvent2	Required	Required	Yes
IDebugCanStopEvent2	Required	Required	No
IDebugDocumentTextEvents2	Not allowed	Not allowed	No
IDebugEngineCreateEvent2	Not allowed	Not allowed	No
IDebugEntryPointEvent2	Required	Required	Yes
IDebugErrorEvent2	Allowed, but not required	Allowed, but not required	Can be
IDebugExceptionEvent2	Required	Required	Yes
IDebugExpressionEvaluationCompleteEvent2	Allowed, but not required	Allowed, but not required	Can be
IDebugInterceptExceptionCompleteEvent2	Required	Required	Yes
IDebugLoadCompleteEvent2	Required	Required	Yes
IDebugMessageEvent2	Allowed, but not required	Allowed, but not required	Can be
IDebugModuleLoadEvent2	Required	Allowed, but not required	No
IDebugOutputStringEvent2	Allowed, but not required	Allowed, but not required	No
IDebugProgramCreateEvent2	Required	Allowed, but not required	No
IDebugProgramDestroyEvent2	Required	Allowed, but not required	No
IDebugPropertyCreateEvent2	Required	Allowed, but not required	No
IDebugPropertyDestroyEvent2	Required	Allowed, but not required	No
IDebugReturnValueEvent2	Allowed, but not required	Allowed, but not required	No
IDebugStopCompleteEvent2	Required	Required	Yes
IDebugStepCompleteEvent2	Required	Required	Yes
IDebugSymbolSearchEvent2	Allowed, but not required	Allowed, but not required	No
IDebugThreadCreateEvent2	Required	Required	No
IDebugThreadDestroyEvent2	Required	Required	No
IDebugThreadNameChangedEvent2	Allowed, but not required	Allowed, but not required	No

See Also

Concepts

Sending Events