This is a function that can be registered as a callback and is invoked every time a message is read by an input node, and before that message is propagated down the message flow. It is invoked for every input message read within the execution group where the callback was registered, if the user exit state is active. The callback is registered by providing a pointer to the function as the iFpInputMessageCallback field of the CCI_UE_VFT struct passed to cciRegisterUserExit.
typedef void (*cciInputMessageCallback) ( CciDataContext* userContext, CciMessage* message, CciMessage* localEnvironment, CciMessage* exceptionList, CciMessage* environment, CciMessageOrigin messageOrigin, CciNode* inputNode);