Python PySerial.How to know if a port is already open?

Question

I'm trying to write an App that uses serial ports in a Linux PC, using python and PySerial. But in this PC there are other Apps using serial ports. How can I know if a port is already open by other App before trying to use it?

thanks

Answer 1

Seems to be badly documented on the PySerial website, this works for me:

ser = serial.Serial(DEVICE,BAUD,timeout=1)
if(ser.isOpen() == False):
    ser.open()

A bit of a contrived example, but you get the idea. I know this question was asked a long time ago, but I had the same question today and felt anyone else finding this page would appreciate finding an answer.

Answer 2

Check the return output of Serial.serial, it returns an invalid exception that can be caught

http://pyserial.sourceforge.net/pyserial_api.html http://pyserial.sourceforge.net/pyserial_api.html#serial.SerialException

Other than that, if the port is in fact closed when your program attempts to access it, the error thrown is non-fatal and is fairly clear about the reason it failed.