LINE_APPNEWCALL message

The TAPI LINE_APPNEWCALL message is sent to inform an application when a new call handle has been spontaneously created on its behalf (other than through an API call from the application, in which case the handle would have been returned through a pointer parameter passed into the function).

        

Parameters

hDevice

The application's handle to the line device on which the call has been created.

dwCallbackInstance

The callback instance supplied when opening the call's line.

dwParam1

Identifier of the address on the line on which the call appears. An address identifier is permanently associated with an address; the identifier remains constant across operating system upgrades.

dwParam2

The application's handle to the new call.

dwParam3

The applications privilege to the new call (LINECALLPRIVILEGE_OWNER or LINECALLPRIVILEGE_MONITOR).

Return value

No return value.

Remarks

Applications supporting TAPI version 2.0 or later are sent a LINE_APPNEWCALL message whenever the application is spontaneously given a handle to a new call. Because the message includes the hLine and dwAddressID parameters on which the call exists, the application can readily create a new call object in the correct context. The LINE_APPNEWCALL message is always immediately followed by a LINE_CALLSTATE message indicating the initial state of the call.

Older applications (that negotiated an API version earlier than 2.0) are sent only a LINE_CALLSTATE message, as documented in previous versions of the API. Such applications would create a new call object upon receiving a LINE_CALLSTATE message that has dwParam3 set to a nonzero value and containing a call handle not presently known by the application. The disadvantages are that (a) the application must call lineGetCallInfo to determine the hLine and dwAddressID parameters associated with the call; (b) the application must scan all known call handles to determine that the call is a new call; and (c) it is possible, under certain conditions, for the application to think it is receiving a new call handle when in reality it has just deallocated its handle to the call (for example, the application has just deallocated a call handle, but a LINE_CALLSTATE message giving the application ownership of the call due to a lineHandoff from another application was already in the application's TAPI message queue).

Requirements

TAPI version
Requires TAPI 2.0 or later
Header
Tapi.h

See also

LINE_CALLSTATE

lineGetCallInfo

lineHandoff