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SysEvent_RegisterForEventNotifications Function

  • Artikkel

Header: #include <applibs/sysevent.h>

Registers the application with a set of events.

Note

There must only be one active EventRegistration struct at a time for all system event notifications.

EventRegistration *SysEvent_RegisterForEventNotifications(EventLoop *el, SysEvent_Events eventBitmask SysEvent_EventsCallback callback_function, void *context);

Parameters

  • el The event loop to which the EventRegistration is registered.

  • eventBitmask A bitmask that indicates the event types to listen to.

  • callbackFunction A function handler that is called when the state of an event in eventBitmask changes.

  • context An optional user context pointer that is passed to the events callback when an event occurs.

Errors

Returns NULL if an error is encountered and sets errno to the error value.

  • EACCES: The application doesn't have the SystemEventNotifications capability.
  • EFAULT: The el or callback_function parameter is NULL.
  • EINVAL: The eventBitmaskspecifies invalid events.

Any other errno may also be specified, but the same behavior might not be retained through system updates.

Return value

Returns a pointer to an EventRegistration struct, or NULL, in which case errno is set to the error value.

Remarks

The EventRegistration struct that is returned needs to be retained until it is passed to SysEvent_UnregisterForEventNotifications.

Application manifest requirements

The application manifest must include the SystemEventNotifications capability.