This message is sent when the specified line device has been forcibly closed. The line device handle or any call handles for calls on the line are no longer valid once this message has been sent.
At a Glance
| Header file: | Tapi.h |
| Windows CE versions: | 1.0 and later |
Syntax
LINE_CLOSE dwDevice = (DWORD) hLine;
dwCallbackInstance = (DWORD) hCallback; dwParam1 = (DWORD) 0;
dwParam2 = (DWORD) 0; dwParam3 = (DWORD) 0;
Parameters
dwDevice
Specifies a handle to the line device that was closed. This handle is no longer valid.
dwCallbackInstance
Specifies the callback instance supplied when opening the line.
dwParam1
Unused.
dwParam2
Unused.
dwParam3
Unused.
Return Values
None.
Remarks
The LINE_CLOSE message is only sent to any application after an open line has been forcibly closed. This can be done to prevent a single application from monopolizing a line device for too long. Whether or not the line can be reopened immediately after a forced close is device-specific.
A line device can also be forcibly closed after the user has modified the configuration of that line or its driver. If the user wants the configuration changes to be effective immediately (as opposed to after the next system restart), and they affect the application’s current view of the device (such as a change in device capabilities), then a service provider can forcibly close the line device.