Raw_input with readline in a daemon thread makes terminal text disappear

John O'Hagan research at johnohagan.com
Fri Oct 16 02:57:45 CEST 2009

I'm getting input for a program while it's running by using raw_input in a 
loop in separate thread. This works except for the inconvenience of not having 
a command history or the use of backspace etc. 

That can be solved by loading the readline module; however, it results in a 
loss of visible access to the terminal when the program ends: nothing is 
echoed to the screen and the history is invisible (although it is there - 
hitting return executes whatever should be there normally). The only way to 
get it back is to close the terminal and open a new one.

Here is minimal code that reproduces the problem (python 2.5 on Linux): 

from threading import Thread
import readline

get_input = Thread(target=raw_input)

If the thread is not set to daemon mode, there is no such problem (don't know 
why this makes a difference), but in the real program, it needs to be a daemon 
or it hangs the exit waiting for more input.

Any suggestions appreciated.



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