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4.19.2 Retrieving UU-IEs
Once the UU-IE access feature is enabled, any User-to-User Information Element received in a
supported message type is made available to the application as a parameter element in a
GC_PARM_BLK that is associated with metaevent for one of the Global Call event types listed in
Table 17. The metaevent is retrieved using the standard gc_GetMetaEvent( ) method and the
parameter element is retrieved from the parameter block using standard Global Call extended
gc_util_..._ex( ) functions.
Note: The application must take care to retrieve the UU-IE information from any incoming message or
copy it to a new location before the next message arrives. The next call to gc_GetMetaEvent( )
will wipe out the metaevent data from the prior event.
In all cases, User-to-User Information Elements are handled as Global Call parameter elements of
the following type:
IPSET_CALLINFO
IPPARM_UUIE_ASN1
• value = octet string containing raw, ASN.1-encoded user-to-user information element
It is the application’s responsibility to decode the ASN.1 data and retrieve any information that is of
interest.
Note: The maximum length for the value of the UU-IE parameter element is max_parm_data_size, which
is configured at library startup (the default value is 255). Any received UU-IE data that exceeds this
maximum length is truncated without notification to the application. When max_parm_data_size is
set to a value larger than 255, the application must use the extended gc_util_..._ex( ) functions
when extracting parameters from a GC_PARM_BLK.
Retrieving UU-IE from Alerting, Connected, Proceeding,
ReleaseComplete, and Setup Messages
To retrieve UU-IE from the Global Call event that notifies the application of an Alerting,
Connected, Proceeding, ReleaseComplete, or Setup message, the application uses
gc_GetMetaEvent( ) to retrieve the metaevent. If the received H.225 message contained a UU-IE,
the GC_PARM_BLK structure pointed to by the extevtdatap field in the METAEVENT structure
will contain a parameter element that has the UU-IE data as its value. The application is then able
to use the gc_util_..._ex( ) functions to extract the ASN.1-encoded data for processing.
Connected GCEV_CONNECTED
Release Complete GCEV_DISCONNECTED
Facility GCEV_EXTENSION (IPEXTID_RECEIVEMSG)
Table 18. H.225 Messages and Global Call Events for Receiving UU-IE
H.225 message Global Call event used to notify application
† The GCEV_PROCEEDING event is maskable.