LINE_LINEDEVSTATE message
The TAPI LINE_LINEDEVSTATE message is sent when the state of a line device has changed. The application can invoke lineGetLineDevStatus to determine the new status of the line.
Parameters
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hDevice
-
A handle to the line device. This parameter is NULL when dwParam1 is LINEDEVSTATE_REINIT.
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dwCallbackInstance
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The callback instance supplied when opening the line. If the dwParam1 parameter is LINEDEVSTATE_REINIT, the dwCallbackInstance parameter is not valid and is set to zero.
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dwParam1
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The line device status item that has changed. The parameter can be one or more of the LINEDEVSTATE_ constants.
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dwParam2
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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.
If dwParam1 is LINEDEVSTATE_REINIT, and the message was issued by TAPI as a result of translation of a new API message into a REINIT message, then dwParam2 contains the dwMsg parameter of the original message (for example, LINE_CREATE or LINE_LINEDEVSTATE). If dwParam2 is zero, this indicates that the REINIT message is a "real" REINIT message that requires the application to call lineShutdown at its earliest convenience.
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dwParam3
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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.
If dwParam1 is LINEDEVSTATE_REINIT, and the message was issued by TAPI as a result of translation of a new API message into a REINIT message, then dwParam3 contains the dwParam1 parameter of the original message (for example, LINEDEVSTATE_TRANSLATECHANGE or some other LINEDEVSTATE_ value, if dwParam2 is LINE_LINEDEVSTATE, or the new device identifier, if dwParam2 is LINE_CREATE).
Return value
No return value.
Remarks
The sending of the LINE_LINEDEVSTATE message can be controlled with lineSetStatusMessages. An application can indicate status item changes about which it wants to be notified. By default, all status reporting is disabled except for LINEDEVSTATE_REINIT, which cannot be disabled. This message is sent to all applications that have a handle to the line, including those that called lineOpen with the dwPrivileges parameter set to LINECALLPRIVILEGE_NONE, LINECALLPRIVILEGE_OWNER, LINECALLPRIVILEGE_MONITOR, or permitted combinations of these.
Requirements
| Requirement | Value |
|---|---|
| TAPI version |
Requires TAPI 2.0 or later |
| Header |
|