I was running some tests and found out that the timeout feature does not work as expected when using the readline (and probably readlines too) method. After digging a bit into the code, I found that readline(256) runs 256 times a read(1) call. Therefore, the timeout is reset for each individual byte, and does not account for the whole 256 bytes reading.
I noticed this issue when running some tests using an incorrect baudrate (9600 instead of the correct 115200), with a simple global timeout of 3000 ms. The readline(256) call terminates after several tens of seconds (value not stable across different repetitions), while the read(256) call correctly terminates after max 3 s (it might return earlier, but returning noise because of wrong baudrate). In my situation, I don't know the baudrate being used, so I need to automatically check if the received data looks correct to validate a baudrate before using it.
Thanks for this great library!
I was running some tests and found out that the timeout feature does not work as expected when using the
readline(and probablyreadlinestoo) method. After digging a bit into the code, I found thatreadline(256)runs 256 times aread(1)call. Therefore, the timeout is reset for each individual byte, and does not account for the whole 256 bytes reading.I noticed this issue when running some tests using an incorrect baudrate (9600 instead of the correct 115200), with a simple global timeout of 3000 ms. The
readline(256)call terminates after several tens of seconds (value not stable across different repetitions), while theread(256)call correctly terminates after max 3 s (it might return earlier, but returning noise because of wrong baudrate). In my situation, I don't know the baudrate being used, so I need to automatically check if the received data looks correct to validate a baudrate before using it.My machine is running on Ubuntu 20.04.