LINE_LINEDEVSTATE

The TSPI LINE_LINEDEVSTATE message is sent to the LINEEVENT callback function when the state of a line device has changed. TAPI can invoke TSPI_lineGetLineDevStatus to determine the new status of the line.

LINE_LINEDEVSTATE
htLine = (HTAPILINE) hLineDevice;
htCall = (HTAPICALL) 0;
dwMsg = (DWORD) LINE_LINEDEVSTATE;
dwParam1 = (DWORD) LineDevState;
dwParam2 = (DWORD) DevStateData1;
dwParam3 = (DWORD) DevStateData2;

Parameters

htLine

The TAPI opaque object handle to the line device.

htCall

Unused.

dwMsg

The value LINE_LINEDEVSTATE.

Specifies the callback instance supplied when opening the line.

dwParam1

Specifies the line device status item that has changed. This parameter uses one or more of the LINEDEVSTATE_ constants

dwParam2

The interpretation of this parameter depends on the value of dwParam1. If dwParam1 is LINEDEVSTATE_RINGING, dwParam2 contains the ring mode with which the switch instructs the line to ring. Valid ring modes are numbers in the range one to dwNumRingModes, where dwNumRingModes is a line device capability.

dwParam3

The interpretation of this parameter depends on the value of dwParam1. If dwParam1 is LINEDEVSTATE_RINGING, dwParam3 contains the ring count for this ring event. The ring count starts at zero.

Remarks

The sending of this message can be controlled through TSPI_lineSetStatusMessages. The service provider must send LINE_LINEDEVSTATE messages for at least the set of status changes selected through that procedure. The service provider can send more than this set, however, it should try to limit its messages to this set for performance reasons. By default all status reporting is disabled.

At the TSPI level, the service provider does not report state changes when the line is opened and closed, since there is only ever one Open outstanding for the device.

For backward compatibility, older service providers would not be expected to generate these values. If they do, TAPI treats them the same as if the service provider were using API version 1.4 or later (as described earlier).

Requirements

  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later.
  Version: Requires TAPI 2.0 or later.
  Header: Declared in Tapi.h.

See Also

LINEDEVSTATUS, LINEEVENT, TSPI_lineGetLineDevStatus, TSPI_lineSetStatusMessages