What is the "1 << 5" meaning in the EventFlags of ANCS

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Created May ’21

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I'm developing the ancs client in a peripheral device. And when i use camera to scan a QR, it will popup a string "Open "xxxxx" in Safari".

This behavior will generate a notification from Notification Source Charateristic. However, the eventflags is 0x30 which the ANCS spec only defined the value from 0x1 to 0x10.

If I try to get the notification attributes with NotificationAttributeIDAppIdentifier, IOS seems in wrongly status and there is no response for get notification attributes.

But without NotificationAttributeIDAppIdentifier, the notification still works.

I'm wondering if the 0x20(1 << 5) is a new type not updated in the ANCS spec? And need speicial handle for this flags?

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Claude31 OP

May ’21

In following doc:
https://developer.apple.com/library/archive/documentation/CoreBluetooth/Reference/AppleNotificationCenterServiceSpecification/Appendix/Appendix.html#//apple_ref/doc/uid/TP40013460-CH3-SW4

eventflag 0x20 is reserved:

EventFlags
Table 3-3
EventFlagsEventFlagSilent = (1 << 0),
EventFlagImportant = (1 << 1),
EventFlagPreExisting = (1 << 2),
EventFlagPositiveAction = (1 << 3),
EventFlagNegativeAction = (1 << 4),
Reserved EventFlags = (1 << 5)–(1 << 7)

But spec has not been updated in this document since 2014. So the flag may now be used.

Note: found an old document (not dated, in chinese), where flags over 0x02 were reserved:
https ://www.programmersought. com/article/51571699993/
https ://www.cnblogs. com/alexcai/p/4321514.html#_EventFlags
which illustrates how reserved flags are progressively used.

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