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Global Call IP Technology Guide — November 2007 407
Dialogic Corporation
reject proposed modification of call attributes — gc_RejectModifyCall( )
attribute modifications are not performed and the call state remains as it was prior to receiving
the incoming re-INVITE request.
GCEV_REJECT_MODIFY_CALL_FAIL
Unsuccessful termination event. Indicates that the signaling of the rejection response failed.
The re-INVITE transaction is still in progress and the application may make another attempt to
respond via a new call to gc_AcceptModifyCall( ) or gc_RejectModifyCall( ). In 1PCC
mode, no modifications to the existing dialog or media session are performed and the current
state remains as it was prior to receiving the incoming re-INVITE request.
Cautions
• This function is only supported when the value of the parameter IPSET_CONFIG /
IPPARM_OPERATING_MODE has been set to IP_T38_MANUAL_MODIFY_MODE using
the gc_SetConfigData( ) function. If this parameter value has not been set, the function call
will fail with an error value of IPERR_BAD_PARM.
• Only one modification transaction can be pending in a call at any given time. Until the pending
re-INVITE has been accepted, rejected, or canceled no additional re-INVITE can be sent by
either party.
• A GCEV_REQ_MODIFY_CALL event can only arrive when a call is connected. But if the
call is dropped—either locally via gc_DropCall( ) or remotely as indicated by a
GCEV_DISCONNECTED event—before a response is initiated via gc_RejectModifyCall( ),
the request is invalid and the response can no longer be sent.
• Only one attempt to respond to a re-INVITE request can be pending at a time. A response
attempt must fail (as indicated by a failure termination event) before a new response is
attempted, otherwise the function call will fail.
Errors
• The function returns GC_ERROR if any of the parameters is invalid, if the call is not in the
connected state, if there is no pending re-INVITE request, or if the value of the configuration
parameter IPSET_CONFIG / IPPARM_OPERATING_MODE has not been set to
IP_T38_MANUAL_MODIFY_MODE in 1PCC operating mode. Use the gc_ErrorInfo( )
function to retrieve further information.
• Upon receiving a GCEV_REJECT_MODIFY_CALL_FAIL event, use the gc_ResultInfo( )
function to retrieve information about the event. See the “Error Handling” section in the
Dialogic
®
Global Call API Programming Guide. All Global Call error codes are defined in the
gcerr.h file while IP-specific error codes are specified in gcip_defs.h. On failure, no
modifications to the existing dialog or media session are performed and the current state
remains as it was prior to the incoming modification request.
Example
The following code example illustrates how the gc_RejectModifyCall( ) function is used in first
party call control (1PCC) operating mode.