Notifies the listener adapter that it is possible to launch other instances of this listener channel.


   IN VOID* pContext,  
   IN LPCWSTR AppPoolId,  
   IN DWORD ListenerChannelId  


[IN] A pointer to a VOID context that the listener adapter passed to WebhostRegisterProtocol.

[IN] A pointer to a string that contains the application pool to which the listener adapter belongs.

[IN] A DWORD that contains the listener channel ID.

Return Value



The listener adapter should call the WebhostOpenListenerChannelInstance function to open the initial listener channel when it receives the first request. The listener adapter should not call WebhostOpenListenerChannelInstance again until it is notified through this function.

This notification can be called whenever a new instance of a listener channel can be connected to a worker process. The following are some of the situations in which this notification may occur:

  • A Web garden contains processes that can either be launched or that are not currently running the processing code for this listener channel.

  • A worker process has idled out and a new one can be launched.

  • A non-overlap recycle process has occurred and a new worker process can be launched.

  • A worker process has terminated unexpectedly and a new one can be launched.

  • The application domain the listener channel was connected to has idled out.

  • The application domain was shut down (for any reason); therefore, the listener channel was stopped and can now be restarted.

The Windows Process Activation Service (WAS) calls this function asynchronously and does not wait for the completion of the notification.


Type Description
Client - IIS 7.0 on Windows Vista
- IIS 7.5 on Windows 7
- IIS 8.0 on Windows 8
- IIS 10.0 on Windows 10
Server - IIS 7.0 on Windows Server 2008
- IIS 7.5 on Windows Server 2008 R2
- IIS 8.0 on Windows Server 2012
- IIS 8.5 on Windows Server 2012 R2
- IIS 10.0 on Windows Server 2016 Technical Preview
Product - IIS 7.0, IIS 7.5, IIS 8.0, IIS 8.5, IIS 10.0
- IIS Express 7.5, IIS Express 8.0, IIS Express 10.0
Header Listeneradapter.h

See Also

Listener Adapter Callback Functions
WebhostRegisterProtocol Function