Opening more than 3 serial ports

[espitall]

• SerialPort Version: 5.0.0

• NodeJS Version: electron 1.6.10 (node 7.4.0)

• Operating System and Hardware Platform: Windows 7 64bits

• Have you checked the right version of the api docs?: yes

• Are you having trouble installing and you checked the Installation Special Cases docs? no

• Are you using Electron and have you checked the Electron Docs?: yes

Summary of Problem

Node-serialport can not open more than 3 serial ports. I am not familiar with node-serialport source code but it seems to start one libuv thread for each opened serial port. Unfortunately the default thread number is pretty low (4) so when 4 serial ports are opened simultaneously it can not respond to any other command (list, close, etc.).

Steps and Code to Reproduce the Issue

• Open 4 serial ports
• Request serialport list => callback never called

[espitall]

More informations :

• setting UV_THREADPOOL_SIZE to an higher number allows more serial ports to be opened

• I have noticed a very high CPU usage even with only one serial port (each port opened seems to use 100% of one core of my CPU) and I have made an ugly hack to fix this by changing
  commTimeouts.ReadIntervalTimeout = MAXDWORD;
  to
  commTimeouts.ReadIntervalTimeout = 10;
  It seems that it also fix the "4 serial ports opened" issue with even with UV_THREADPOOL_SIZE set to 4 (default value).

[espitall]

Just found that my issue report is a duplicate #1221. Sorry for the noise...
Please consider adding a note on the README file about this limitation on windows platform.

Can you tell me if I can keep by little hack ('commTimeouts.ReadIntervalTimeout = 10;' -- which also address the high CPU usage) or does it will cause others issues ?

[reconbot]

I don't know if it would cause issues or not. I'd guess not. You can tell us for sure. =)

Added the note!

[reconbot]

I also added a note saying we really do need help to close #1221 it's a bit beyond my abilities with windows c++. I've put quite a few hours into it but I have a hard time debugging.