lineSetNumRings

The lineSetNumRings function sets the number of rings that must occur before an incoming call is answered. This function can be used to implement a toll-saver-style function. It allows multiple independent applications to each register the number of rings. The function lineGetNumRings returns the minimum number of rings requested. It can be used by the application that answers incoming calls to determine the number of rings it should wait before answering the call.

LONG WINAPI lineSetNumRings(
  HLINE hLine,        
  DWORD dwAddressID,  
  DWORD dwNumRings    
);

Parameters

hLine

A handle to the open line device.

dwAddressID

An address on the line device. An address identifier is permanently associated with an address; the identifier remains constant across operating system upgrades.

dwNumRings

The number of rings before a call should be answered in order to honor the toll-saver requests from all applications.

Return Values

Returns zero if the request succeeds or a negative error number if an error occurs. Possible return values are:

LINEERR_INVALLINEHANDLE, LINEERR_OPERATIONFAILED, LINEERR_INVALADDRESSID, LINEERR_RESOURCEUNAVAIL, LINEERR_NOMEM, LINEERR_UNINITIALIZED.

Remarks

The lineGetNumRings and lineSetNumRings functions, when used in combination, provide a mechanism to support the implementation of toll-saver features across multiple independent applications. If no application ever calls lineSetNumRings, lineGetNumRings returns 0xFFFFFFFF.

An application that is the owner of a call in the offering state and that received 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. A separate LINE_LINEDEVSTATE ringing message is sent to the application for each ring cycle, so the application should count these messages. If this call disconnects before being answered, and another call comes in shortly thereafter, the LINE_CALLSTATE message should allow the application to determine that ringing is related to the second call.

If call classification is performed by TAPI by means of answering incoming calls of unknown media type and filtering the media stream, TAPI honors this number as well.

Note  This operation is purely informational and does not affect the state of any calls on the line device.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later.
  Version: Requires TAPI 1.3 or later.
  Header: Declared in Tapi.h.
  Library: Use Tapi32.lib.

See Also

TAPI 2.2 Reference Overview, Basic Telephony Services Reference, LINE_CALLSTATE, LINE_LINEDEVSTATE, lineGetNumRings