Platform SDK: TAPI |
The lineForward function forwards calls destined for the specified address on the specified line, according to the specified forwarding instructions. When an originating address (dwAddressID) is forwarded, the specified incoming calls for that address are deflected to the other number by the switch. This function provides a combination of forward and do-not-disturb features. This function can also cancel forwarding currently in effect.
LONG WINAPI lineForward( HLINE hLine, DWORD bAllAddresses, DWORD dwAddressID, LPLINEFORWARDLIST const lpForwardList, DWORD dwNumRingsNoAnswer, LPHCALL lphConsultCall, LPLINECALLPARAMS const lpCallParams );
An address identifier is permanently associated with an address; the identifier remains constant across operating system upgrades.
Returns a positive request identifier if the function is completed asynchronously, or a negative error number if an error occurs. The dwParam2 parameter of the corresponding LINE_REPLY message is zero if the function succeeds or it is a negative error number if an error occurs. Possible return values are:
LINEERR_INVALLINEHANDLE, LINEERR_NOMEM, LINEERR_INVALADDRESSID, LINEERR_OPERATIONUNAVAIL, LINEERR_INVALADDRESS, LINEERR_OPERATIONFAILED, LINEERR_INVALCOUNTRYCODE, LINEERR_RESOURCEUNAVAIL, LINEERR_INVALPOINTER, LINEERR_STRUCTURETOOSMALL, LINEERR_INVALPARAM, LINEERR_UNINITIALIZED.
A successful forwarding indicates only that the request has been accepted by the service provider, not that forwarding is set up at the switch. A LINE_ADDRESSSTATE (forwarding) message provides confirmation for forwarding having been set up at the switch.
Forwarding of the address(es) remains in effect until this function is called again. The most recent forwarding list replaces the old one. Forwarding can be canceled by specifying a NULL pointer as lpForwardList. If a NULL destination address is specified for an entry in the forwarding list, the operation acts as a do-not-disturb.
Forwarding status of an address can also be affected externally; for example, by administrative actions at the switch or by a user from another station. It may not be possible for the service provider to be aware of this state change, and it may not be able to keep in synchronization with the forwarding state known to the switch.
Because a service provider may not know the forwarding state of the address "for sure" (that is, it may have been forwarded or unforwarded in an unknown way), lineForward succeeds unless it fails to set the new forwarding instructions. In other words, a request that all forwarding be canceled at a time that there is no forwarding in effect is successful. This is because there is no "unforwarding"—you can only change the previous set of forwarding instructions.
The success or failure of this operation does not depend on the previous set of forwarding instructions, and the same is true when setting different forwarding instructions. The provider should "unforward everything" prior to setting the new forwarding instructions. Because this can take time in analog telephony environments, a provider may also want to compare the current forwarding with the new one, and only issue instructions to the switch to get to the final state (leaving unchanged forwarding unaffected).
Invoking lineForward when LINEFORWARDLIST has dwNumEntries set to zero has the same effect as providing a NULL lpForwardList parameter. It cancels all forwarding currently in effect.
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.
Unicode: Implemented as Unicode and ANSI versions on all platforms.
Forward Overview, TAPI 2.2 Reference Overview, Supplementary Line Service Functions, LINE_ADDRESSSTATE, LINE_REPLY, LINECALLPARAMS, LINEFORWARDLIST