1.3.12. Events

All type of events are handled in the runtime system by the event manager component CmpEventMgr. We separate here two different kind of event users:

• Provider: Component, that provides an event

• Consumer: Component, that uses an event

The CmpEventMgr has routines for providers to create and delete and event.

For the consumer, there are routines to open and close events and to register callbacks to an event. Callbacks can be functions or methods of objects (this works with C, C++ and IEC consumers).

One event is always structured as followed:

typedef struct
{
 EVENTID EventId;
 CMPID CmpIdProvider;
 unsigned short usParamId;
 unsigned short usVersion;
 void *pParameter;
 void *pUserParameter;
} EventParam;

The event Id consists of the high word with the event class and the low word with the event Id. The event class can be one of the following:

#define EVTCLASS_INFO 0x00010000
#define EVTCLASS_WARNING 0x00020000
#define EVTCLASS_ERROR 0x00040000
#define EVTCLASS_EXCEPTION 0x00080000
#define EVTCLASS_VENDOR_SPEC 0x10000000

The event Id is unique for each component, but not unique in the runtime system! Only the combination of the event Id and the component Id makes an event unique!

The second parameter of an event is the component Id of the provider.

The parameter Id and the version specify the parameter that is provided by the pointer pParam. Every provider has to specify a structure with a specific parameter Id that is sent in pParameter.

The last parameter can be a parameter that is specified by the consumer at register a callback. This parameter is sent back with the event.