Why's select() always blocked in non-blocking mode

Question

Although I set socket in non-blocking, seclect() function is still blocked. Please help me.

this is my code:

import socket
import select
if __name__ == '__main__':
   server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
   server.bind(("localhost",9006))
   server.listen(10)
   server.setblocking(False)
   inputs = [server]
   while True:
      try:
         a,b,c = select.select(inputs, [], [])
      except Exception:
        print ("exception")
      print ("Timeout") 

Answer 1

From the select docs:

The optional timeout argument specifies a time-out as a floating point number in seconds. When the timeout argument is omitted the function blocks until at least one file descriptor is ready.

In other words, socket 'blocking' state is not relevant here. You need to specify any timeout to disable blocking; you can set 0 to make it return immediately when there is nothing to read (but note that then your loop will occupy CPU heavily).

For example:

a,b,c = select.select(inputs, [], [], 0)