Pyserial using default system serial configuration

I've investigated pySerial's source code. It seems this is not possible. PySerial has a set of defaults. And if I'm not mistaken, when you call open() method it will always configure port to these defaults or whatever setting you changed them to.

This is the relevant bit from the implementation of Serial::open() method:

def open(self):
 """\
 Open port with current settings. This may throw a SerialException
 if the port cannot be opened."""
 # ... ...
 # open
 try:
 self.fd = os.open(self.portstr, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK)
 except OSError as msg:
 self.fd = None
 raise SerialException(msg.errno, "could not open port %s: %s" % (self._port, msg))
 #~ fcntl.fcntl(self.fd, fcntl.F_SETFL, 0) # set blocking
 try:
 # **this is where configuration occurs**
 self._reconfigure_port(force_update=True)
 except:
 try:
 os.close(self.fd)
 except:
 # ignore any exception when closing the port
 # also to keep original exception that happened when setting up
 pass
 self.fd = None
 raise
 else:

https://github.com/pyserial/pyserial/blob/master/serial/serialposix.py#L299

I see two alternatives for you; get the settings that you are interested from the system (using stty maybe) before calling Serial::open() and set these settings explicitly.

Another option is to subclass PySerial's Serial class, re implement ::open() method, skip the configuration part:

 # self._reconfigure_port(force_update=True)

I'm not sure if that would work though. It may cause problems, because other parts of the implementation are expecting port to be in a specific configuration, but it isn't.

UPDATE: I think a better implementation of open() method would read the settings from the opened port and set necessary attributes/properties of the Serial object to reflect these settings.

• python
• serial-port
• pyserial