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lineAnswer
The lineAnswer function answers the specified offering call.
LONG lineAnswer(
HCALL hCall,
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| LPCSTR lpsUserUserInfo,
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| DWORD dwSize
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| );
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Parameters
hCall
A handle to the call to be answered. The application must be an owner of this
call. The call state of hCall must be offering or accepted.
lpsUserUserInfo
A pointer to a string containing user-to-user information to be sent to the
remote party at the time of answering the call. This pointer can be left NULL if
no user-to-user information is to be sent. User-to-user information is only
sent if supported by the underlying network (see LINEDEVCAPS). The protocol discriminator field for the user-to-user information, if
required, should appear as the first byte of the buffer pointed to by lpsUserUserInfo, and must be accounted for in dwSize.
dwSize
The size in bytes of the user-to-user information in lpsUserUserInfo. If lpsUserUserInfo is NULL, no user-to-user information is sent to the calling party and dwSize is ignored.
Return Values
Returns a positive request ID if the function will be completed
asynchronously, or a negative error number if an error has occurred. The dwParam2 parameter of the corresponding LINE_REPLY message is zero if the function is successful or it is a negative error
number if an error has occurred. Possible return values are:
LINEERR_INUSE, LINEERR_OPERATIONUNAVAIL, LINEERR_INVALCALLHANDLE,
LINEERR_OPERATIONFAILED, LINEERR_INVALCALLSTATE, LINEERR_RESOURCEUNAVAIL,
LINEERR_INVALPOINTER, LINEERR_UNINITIALIZED, LINEERR_NOMEM, LINEERR_USERUSERINFOTOOBIG,
LINEERR_NOTOWNER.
Remarks
When a new call arrives, applications with an interest in the call are sent a LINE_CALLSTATE message to provide the new call handle and to inform the application about
the call's state and the privileges to the new call (such as monitor or owner).
The application with owner privilege for the call can answer this call using lineAnswer. After the call has been successfully answered, the call typically
transitions to the connected state. Initially, only one application is given owner privilege to the
inbound call.
In some telephony environments (like ISDN), where user alerting is separate
from call offering, the application may have the option to accept a call prior to
answering or to reject or redirect the offering call.
If a call comes in (is offered) at the time another call is already active,
the new call is connected to by invoking lineAnswer. The effect this has on the existing active call depends on the line's device
capabilities. The first call may be unaffected, it may automatically be
dropped, or it may automatically be placed on hold. The appropriate LINE_CALLSTATE
messages report state transitions to the application about both calls.
In a bridged situation, if a call is connected but in the
LINECONNECTEDMODE_INACTIVE state, it may be joined using the lineAnswer function.
The application has the option to send user-to-user information at the time of
the answer. Even if user-to-user information can be sent, there is no
guarantee that the network will deliver this information to the calling party. An
application should consult a line's device capabilities to determine whether sending
user-to-user information upon answering the call is available.
See Also
LINE_CALLSTATE, LINE_REPLY, LINEDEVCAPS
Related Links
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