[mungoman2]

No, the author can use all entries in the buffer. The space cost is hidden in that one of the pointers need to hold X+1 values, ie for 256 entries it is not enough with 8-bit indices.

An unfortunate effect of this implementation is that both indices are modified by the consumer. It's not safe to write/read dats from different contexts, something that would be very useful in a driver.

[codehero]

Yeah your intuition is correct here. On an MSP430 (which is were I use it) the producer is in interrupt context but as a savvy redditor pointed out, I will need to enable/disable interrupts in the consumer function as well.

[rhaps0dy]

Ah, thanks for explaining.

Now it makes sense.