PHONE_CLOSE  1MGCNBJ

The PHONE_CLOSE message is sent when an open phone device has been forcibly closed as part of resource reclamation. The device handle is no longer valid once this message has been sent.

PHONE_CLOSE
hPhone = (HPHONE) hPhoneDevice;

    dwCallbackInstance = (DWORD) hCallback;

    dwParam1 = (DWORD) 0;

    dwParam2 = (DWORD) 0;

    dwParam3 = (DWORD) 0;

Parameters

hPhone

A handle to the open phone device that was closed. The handle is no longer valid after this message has been sent

dwCallbackInstance

The application's callback instance provided when opening the phone device.

dwParam1

Unused.

dwParam2

Unused.

dwParam3

Unused.

Return Values

No return value.

Remarks

The PHONE_CLOSE message is only sent to an application after an open phone has been forcibly closed. This may be done to prevent a single application from monopolizing a phone device for too long. Whether the phone can be reopened immediately after a forced close is device specific.

An open phone device may also be forcibly closed after the user has modified the configuration of that phone or its driver. If the user wants the configuration changes to be effective immediately (as opposed to after the next system restart), and these changes affect the application's current view of the device (such as a change in device capabilities), then a service provider may forcibly close the phone device.