ESPNow.recv(timeout)

[mmliam]

I understand that "timeout" is in milliseconds, if left empty defaults to 5 minutes and if <0 does not return on timeout.
What is the maximum "timeout" can be set in milliseconds; is it 2**32ms?

MM

[glenn20]

I just checked the code as I was preparing my answer and realised that I think there is a regession in my code.

The maximum SHOULD be (2**31-1)ms (ie. 24 days), but I have been handling the negative value case incorrectly (I believe I fixed this some time ago - but noticed what I thought was my old code still in use).

From inspection of the espnow-v1.19.1 and espnow-g20 braches:

• the maximum safe value for timeout should be 2**31-1;
• negative values of timeout are being set to numbers over 2**31; and
• numbers larger than 2**32 will either:
  • throw an exception (I believe this is the case); or
  • be truncated to 32 bits (depending on behaviour of mp_obj_get_int()).

Thanks for prompting me to check this. I'll run some tests and update my code.

[mmliam]

Thanks Glenn, sorry for the late reply.

I don't intend on pushing the MAX; I was just curious what the MAX was as I couldn't find any documentation.

MM

[glenn20]

Ive pushed a commit that changes the timeout behaviour:

• timeout == 0: Do not wait: return (None, None) if no messages available.
• -2**31+1 <= timeout < 0: Disable timeout: will wait forever for a message.
• 0 < timeout <= 2**31-1: Set timeout to that number of milliseconds.
• 2**31 <= timeout || timeout <= -2**31: Raise OverflowError.