Keyboard input with timeout?

Question

How would you prompt the user for some input but timing out after N seconds?

Google is pointing to a mail thread about it at http://mail.python.org/pipermail/python-list/2006-January/533215.html but it seems not to work. The statement in which the timeout happens, no matter whether it is a sys.input.readline or timer.sleep(), I always get:

<type 'exceptions.TypeError'>: [raw_]input expected at most 1 arguments, got 2 

which somehow the except fails to catch.

Answer 1

Using a select call is shorter, and should be much more portable

import sys, select  print "You have ten seconds to answer!"  i, o, e = select.select( [sys.stdin], [], [], 10 )  if (i):   print "You said", sys.stdin.readline().strip() else:   print "You said nothing!" 

Answer 2

The example you have linked to is wrong and the exception is actually occuring when calling alarm handler instead of when read blocks. Better try this:

import signal TIMEOUT = 5 # number of seconds your want for timeout  def interrupted(signum, frame):     "called when read times out"     print 'interrupted!' signal.signal(signal.SIGALRM, interrupted)  def input():     try:             print 'You have 5 seconds to type in your stuff...'             foo = raw_input()             return foo     except:             # timeout             return  # set alarm signal.alarm(TIMEOUT) s = input() # disable the alarm after success signal.alarm(0) print 'You typed', s