Handle SystemExit exception

[Steven D'Aprano]

asit wrote:

> My program contains some sys.exit(1) and when its executed an
> exception known as SystemExit is thrown.
> 
> I tried to handle bu using following code snippet
> 
> if __name__ == "__main__":
>     try:
>         main()  #main contains sys.exit(1)
>     except KeyboardInterrupt:
>         print "aborted by user"
>     except SystemExit:
>         pass
> 
> But it does not work.

It works for me:

>>> try:
...     sys.exit()
... except SystemExit:
...     pass
... 
>>> 


What does it do for you? Crash? Exit? print garbage to the screen?


I'm going to guess what you are doing. Do you have code like this?

try:
    main()  #main contains sys.exit(1)
except KeyboardInterrupt:
    print "aborted by user"
except SomeOtherException, SystemExit:
    pass

This will mask SystemExit and stop it from being caught. It should be
written like this:

except (SomeOtherException, SystemExit):
    pass



Or possibly something like this?

try:
    main()  #main contains sys.exit(1)
except KeyboardInterrupt:
    print "aborted by user"
except Exception:
    do_something()
    raise
except SystemExit:
    pass

The Exception clause will catch SystemExit before the SystemExit clause will
see it. That should be written like this:


except SystemExit:
    pass
except Exception:
    do_something()
    raise




-- 
Steven