Re: [Newbie] Problem receiving data with asio::serial_port

From: Ruben Perez (rubenperez038_at_[hidden])
Date: 2024-06-06 13:57:01

Try re-creating the serial port object on timeout.

If I'm not mistaken, error code 89 on OSX means ECANCELED.

>From reading
https://github.com/fedetft/serial-port/blob/master/2_with_timeout/TimeoutSerial.h,
I'd say that the class is not handling cancellations correctly. When a
timeout occurs, serial_port::cancel gets called, which in turns makes the
operation complete with a ECANCELED error code (which BTW has a different
number for each platform). This line is handling the case for Linux:
https://github.com/fedetft/serial-port/blob/291a7997a665a52bf37d15c615679445724cf453/2_with_timeout/TimeoutSerial.cpp#L240.
But it's failing to do so for OSX.

https://github.com/fedetft/serial-port/blob/master/2_with_timeout/TimeoutSerial.h
does several questionable things:
- io_service name has been deprecated long ago (in favor of io_context)
- error codes should be checked by name, and not by number (hence avoiding
problems like the one you encountered)
- If you're creating more than one serial port in your application, this
creates an io_service per object, which incurs in _a lot_ of overhead.
- The way it handles cancellation is not ideal - it should wait until both
async operations finish before returning or throwing the relevant exception.

You'll probably need to do some cleanup there before proceeding.

If you need more help, it may be faster to ask in the #boost-asio channel
in Slack: https://cpplang.slack.com/archives/C06BRML5EFK

Hope it helps.

Ruben.