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LINE_APPNEWCALL (Compact 2013)

  • Статья

3/26/2014

This 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 this case the handle would have been returned through a pointer parameter passed into the function.

Syntax

LINE_APPNEWCALL
    hDevice = (DWORD) hLine;
    dwCallbackInstance = (DWORD) dwInstanceData;
    dwParam1 = (DWORD) dwAddressID;
    dwParam2 = (DWORD) hCall;
    dwParam3 = (DWORD) dwPrivilege;

Parameters

  • hDevice
    Application's handle to the line device on which the call has been created.
  • dwCallbackInstance
    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
    Application's handle to the new call.
  • dwParam3
    Applications privilege to the new call (LINECALLPRIVILEGE_OWNER or LINECALLPRIVILEGE_MONITOR).

Return Value

None.

Remarks and Backward Compatibility

Applications supporting TAPI 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 (TAPI) 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 the lineGetCallInfo function 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

Header

tapi.h

See Also

Reference

TAPI Messages
lineGetCallInfo
lineHandoff
LINE_CALLSTATE (TAPI)