LINE_CREATE message
The TSPI LINE_CREATE message is sent to the LINEEVENT callback function when it desires to create a new device. This can occur when a new device is detected by Plug and Play, or dynamically enabled by the user through a provider configuration function. During the LINEEVENT callback procedure, TAPI simply queues this message for later processing. When the message is received from the queue, the TSPI_providerCreateLineDevice function is called in the context of the TAPISRV process.
LINE_CREATE
htLine = (HTAPILINE) 0;
htCall = (HTAPICALL) 0;
dwMsg = (DWORD) LINE_CREATE;
dwParam1 = (DWORD) hProvider;
dwParam2 = (DWORD) TempDeviceId;
dwParam3 = (DWORD) 0;
Parameters
htLine
Unused.htCall
Unused.dwMsg
The value LINE_CREATE.dwParam1
The service provider handle (hProvider) as received in TSPI_providerEnumDevices.dwParam2
Contains a temporary device identifier generated by the service provider. TAPI uses this value in a subsequent call to TSPI_providerCreateLineDevice to assist the provider in associating the message and the function call (in the event that multiple devices are being created).dwParam3
Unused.
Return value
This message has no return values.
Remarks
Service providers can (and should) continue to make "static" device allocations at startup when TAPI calls TSPI_providerEnumDevices. Creating known devices using this mechanism, instead of always using LINE_CREATE, involves lower overhead for applications (because they don't have to process LINE_CREATE messages, updated device information, and so on). The LINE_CREATE mechanism is intended to be used only if new devices are created while the service provider is active (for example, between TSPI_providerInit and TSPI_providerShutdown).
This message is sent to the LINEEVENT callback entry point in TAPI. The service provider receives a pointer to this callback in the TSPI_providerEnumDevices function and in each TSPI_lineOpen function; the LINE_CREATE message can be sent to the callback function given to any open line or LINEEVENTat startup.
For backward compatibility, older service providers are not expected to send this message. If they do, the message is treated in the same manner as described earlier for new service providers.
Requirements
TAPI version |
Requires TAPI 2.0 or later |
Header |
Tapi.h |