IPrintAsyncNotifyCallback::ChannelClosed method (prnasnot.h)

Advises one member of a communication channel to notify the other member that the channel is being closed.

Syntax

HRESULT ChannelClosed(
  [in] IPrintAsyncNotifyChannel    *pChannel,
  [in] IPrintAsyncNotifyDataObject *pData
);

Parameters

[in] pChannel

A pointer to the channel used by the sender and the listener.

[in] pData

A pointer to the object that contains the notification data or response.

Return value

The return values are COM error codes. Because this function might complete the operation successfully yet return an HRESULT other than S_OK you should use the SUCCEEDED or FAILED macro to determine the success of the call. To get the specific HRESULT that was returned by the function, use the HRESULT_CODE macro.

See PrintAsyncNotifyError for other possible return values.

For more information about COM error codes, see Error Handling.

The following code example shows how these macros can be used to evaluate the return value.

if (SUCCEEDED(hr)){
  // Call was successful 
}

if (FAILED(hr)) {
  // Call failed 
}

if (FAILED(hr)) {
  // Call failed, check HRESULT value returned
  switch (HRESULT_CODE(hr)){
    case CHANNEL_ALREADY_CLOSED:
      // Some action 
      break;
    default:
      // Default action 
      break;
  }
} else {
  // Call succeeded 
}

Remarks

When a component that is hosted by the print spooler closes a communication channel with a listening application, the component should call the ChannelClosed method of the IPrintAsyncNotifyCallback object, which the listening application provided at the time it registered for notifications. If the print server crashes, the print spooler will attempt to call the OnEventNotify method of the IPrintAsyncNotifyCallback object provided by the listening application. It will send a notification of type NOTIFICATION_RELEASE.

If the listening application closes a bidirectional communication channel, it should call the ChannelClosed method of the IPrintAsyncNotifyCallback object provided by the component when it created the channel. If the listening application crashes, the print spooler will call the OnEventNotify method of the IPrintAsyncNotifyCallback object provided by the component that is hosted by the print spooler. It will send a notification of type NOTIFICATION_RELEASE.

Requirements

See also

Asynchronous Printing Notification Interfaces

Error Handling

IPrintAsyncNotifyCallback

Printing