Question

I’m trying to read a serial port in Ruby using the serial port gem. The problem is that sometimes there is not data to be read and when I tell the program to read the serial port, the program hangs… I’ve tried using sp.read, sp.readline and sp.readlines; they all cause the program to block (under Windows).

Does anybody know if there is a way that will not cause blocking? Basically, I want that if there be no data to read, the

read result be nil.

Thanks.

Answer 1

You could use IO#read_nonblock:

begin
  result = io.read_nonblock(maxlen)
rescue IO::WaitReadable # this is raised when there's no data in the stream
  # don't wait and return nil
  result = nil
end