LINE_MONITORMEDIA

The TAPI LINE_MONITORMEDIA message is sent when a change in the call's media type is detected. The sending of this message is controlled with the lineMonitorMedia function.

LINE_MONITORMEDIA
hDevice = (DWORD) hCall;
dwCallbackInstance = (DWORD) hCallback;
dwParam1 = (DWORD) MediaMode;
dwParam2 = (DWORD) 0;
dwParam3 = (DWORD) TickCount;

Parameters

hDevice

A handle to the call.

dwCallbackInstance

The callback instance supplied when opening the line.

dwParam1

The new media type (or mode). This parameter must be one and only one of the LINEMEDIAMODE_ constants.

dwParam2

Unused.

dwParam3

The "tick count" (number of milliseconds since Windows started) at which the specified media was detected. For TAPI versions earlier than 2.0, this parameter is unused.

Return Values

No return value.

Remarks

The LINE_MONITORMEDIA message is sent to the application that has enabled media monitoring for the media type detected.

Because this timestamp may have been generated on a computer other than the one on which the application is executing, it is useful only for comparison to other similarly timestamped messages generated on the same line device (LINE_GATHERDIGITS, LINE_GENERATE, LINE_MONITORDIGITS, LINE_MONITORTONE), in order to determine their relative timing (separation between events). The tick count can "wrap around" after approximately 49.7 days; applications must take this into account when performing calculations.

If the service provider does not generate the timestamp (for example, if it was created using an earlier version of TAPI), then TAPI provides a timestamp at the point closest to the service provider generating the event so that the synthesized timestamp is as accurate as possible.

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

LINE_GATHERDIGITS, LINE_GENERATE, LINE_MONITORDIGITS, LINE_MONITORTONE