The lineGetNumRings function determines the number of rings an incoming call on the given address should ring prior to answering the call.
LONG lineGetNumRings(
HLINE hLine,
DWORD dwAddressID,
LPDWORD lpdwNumRings
);
Returns zero if the request succeeds or a negative error number if an error occurs. Possible return values are:
LINEERR_INVALADDRESSID, LINEERR_OPERATIONFAILED, LINEERR_INVALLINEHANDLE, LINEERR_RESOURCEUNAVAIL, LINEERR_INVALPOINTER, LINEERR_UNINITIALIZED, LINEERR_NOMEM.
The lineGetNumRings and lineSetNumRings functions, when used in combination, provide a mechanism to support the implementation of toll-saver features across multiple independent applications.
An application that receives a handle for a call in the offering state and a LINE_LINEDEVSTATE ringing message should wait a number of rings equal to the number returned by lineGetNumRings before answering the call in order to honor the toll-saver settings across all applications. The lineGetNumRings function returns the minimum of all applications' number of rings specified by lineSetNumRings. Because this number can vary dynamically, an application should invoke lineGetNumRings each time it has the option to answer a call. If no application has called lineSetNumRings, the number of rings returned is 0xFFFFFFFF. A separate LINE_LINEDEVSTATE ringing message is sent to the application for each ring cycle.
If call classification is performed by TAPI of answering all calls of unknown media mode and filtering the media stream, TAPI honors this number as well.
Note This operation is purely informational and does not in itself affect the state of any calls on the line device.
Version: Use TAPI version 1.4 and later.
Header: Declared in tapi.h.
Import Library: Link with tapi32.lib.
TAPI Reference Overview, Basic Telephony Services Reference, LINE_LINEDEVSTATE, lineSetNumRings