calling a program without waiting for it to finish
donn at drizzle.com
Fri Mar 21 05:29:08 CET 2003
Quoth Alex Martelli <aleax at aleax.it>:
| You can take specific, platform-dependent action to terminate such
| processes in a function run at your Python program's termination
| (see standard library module atexit). E.g., killall will work on some
| systems for such purposes.
os.spawnv(os.P_NOWAIT, '/bin/ping', ['ping', 'www.python.org'])
- spawnv() invokes the specified command directly without a shell,
which is particularly advantageous when the command is calculated
from input data and therefore not reliably safe from shellisms
that could radically affect your command.
- The above works only when the python script was started directly
from an interactive shell, in which case (assuming Berkeley job
control) it will be a process group leader - running in its own
process group, with process group ID == process ID. Any process
forked by the python script will belong to that same process group.
- kill(-n, x) means send signal x to process group n. I expect that
may be enshrined in POSIX 1003.1, don't know for sure though.
- signal(SIG_IGN,) is to survive my own signal.
- You can use setpgrp() to effect more elaborate process control,
but not often will it be worth the trouble.
Donn Cave, donn at drizzle.com
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