2.18. gc_ReleaseCallEx( )

The gc_ReleaseCallEx( ) function must be called after a gc_DropCall( ) function terminates. If a previous gc_WaitCall( ) function was issued synchronously, then once the gc_ReleaseCallEx( ) function is issued, an inbound call is either:

• routed to a different line device if channel selection is preferred
• rejected until the gc_WaitCall( ) function is issued again

When the gc_WaitCall( ) function is used in synchronous mode and the gc_ReleaseCallEx( ) function is issued subsequently, the next inbound call on the same channel will be pending until the gc_WaitCall( ) function is issued again. If the gc_WaitCall( ) function is used in asynchronous mode, the inbound call notification can be received immediately after the gc_ReleaseCallEx( ) function.

Under PRI, the firmware sends the RELEASE message to the network automatically, by default. However, the host can be configured to control when to send the RELEASE message to the network by using a parameter configuration file set prior to download time. Unlike PRI, the BRI board passes this control to the host application by default. The host application then sends the RELEASE message through the gc_ReleaseCall( ) function. See Figure6, Network Initiated Inbound Call (Synchronous Mode), for more information on how to use this function.

Cautions

Under load conditions, or if the remote end delays transmitting the RELEASE COMPLETE message, an application could experience a significant delay while the cc_ReleaseCall( ) function unblocks and returns control to the application. This delay can be up to 8 seconds long if the RELEASE COMPLETE message is never returned. The cc_ReleaseCall( ) function is supported only in synchronous mode; therefore, this problem occurs only in applications that use the asynchronous single-threaded programming model. In this case, when this blocking function is called within a handler processing the CCEV_DROPCALL event, it could create a bottleneck for processing any other event and, thereby, could affect call-handling performance.

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