CBCharacteristicWriteWithoutResponse

As the title suggests, I would like to know whether writes to CBPeripherals using CBCharacteristicWriteWithoutResponse return instantly (and do the writing on another thread) or return only when the write is complete.


I would expect the latter, but a colleague of mine has given me reason to believe the former might be true (he's seeing packets not being sent by the iOS device when repeatedly writing).

Replies

The data is copied and the function returns. The method does not wait for the write to complete.


If the write buffers fill, the data will get silently discarded using this method. That could be what your colleague is seeing.