[Tutor] Kill A Fuction Call?

[Jeff Shannon]

Scott wrote:

>Is it possible to call a function, and kill it if it doesn't complete in
>a certain amount of time?
>  
>

Sort of, but not easily, and the method of doing so depends on whether 
you're writing the function yourself.  If you *are*, then the simplest 
way is to have the function code periodically check a timer and abort 
itself if it's taken too long.  (This can be combined with threads -- 
have the function's worker thread check a simple 'abort' flag, and have 
a timer or other function set that flag as needed.)

If you do not have control over the function, then this is a very 
difficult thing.  Threads won't work, because Python won't let you kill 
threads from outside, as you already know.  You *can* run the function 
in a separate process, using standard IPC mechanisms like pipes, because 
processes (unlike threads) can be killed -- but processes are also 
rather heavier and more awkward to use.  Depending on just what it is 
that you're doing, there may be some way around the limitations, too -- 
if you're waiting on a socket connection, say, there's a timeoutsocket 
module available that will do this for you.

Jeff Shannon
Technician/Programmer
Credit International