LINEEVENT callback function (tspi.h)

Line_Event is a callback function implemented by TAPI and supplied to the service provider as a parameter to TSPI_lineOpen. The service provider calls this function to report events that occur on the line or on calls on the line.

The LINEEVENT type defines a pointer to this callback function. Line_Event is a placeholder for the application-defined function name.

Syntax

LINEEVENT Lineevent;

void Lineevent(
  HTAPILINE htLine,
  HTAPICALL htCall,
  DWORD dwMsg,
  DWORD_PTR dwParam1,
  DWORD_PTR dwParam2,
  DWORD_PTR dwParam3
)
{...}

Parameters

htLine

The TAPI handle for the line on which the event occurred.

htCall

The TAPI handle for the call on which the event occurred if this is a call-related event. For line-related events where there is no call, this parameter is set to NULL.

dwMsg

Specifies the kind of event that is being reported. Interpretation of the other parameters is performed in different ways according to the context indicated by dwMsg.

dwParam1

A parameter for the message.

dwParam2

A parameter for the message.

dwParam3

A parameter for the message.

Return value

None

Remarks

The call state when calling this function can be any state.

The service provider passes the HTAPILINE value supplied to TSPI_lineOpen as the htLine parameter. It includes the message identifier and parameters specific to the event.

This function differs from the callback function defined at the TAPI level in that it separates line and call parameters. Both parameters are used for some messages. The sets of messages that can be passed to this procedure differ slightly from the TAPI level. In particular, completion of asynchronously executing requests is reported through the Completion_Proc callback instead of this one.

Requirements

Requirement	Value
Target Platform	Windows
Header	tspi.h

See also

Completion_Proc

TSPI_lineOpen