Question

Is it bad form to exit() from within function?

def respond_OK():
    sys.stdout.write('action=OK\n\n')
    sys.stdout.flush() # redundant when followed by exit()
    sys.exit(0)

Rather than setting an exit code and exit()ing from the __main__ name space?

def respond_OK():
    global exit_status
    sys.stdout.write('action=OK\n\n')
    sys.stdout.flush()
    exit_status = 0

sys.exit(exit_status)

The difference is negligible from a function perspective, just wondered what the consensus is on form. If you found the prior in someone else’s code, would you look at it twice?

Answer 1

I would prefer to see an exception raised and handled from a main entry point, the type of which is translated into the exit code. Subclassing exceptions is so simple in python it’s almost fun.

As posted in this answer’s comments: Using sys.exit also means that the point of termination needs to know the actual status code, as opposed to the kind of error it encountered. Though that could be solved by an set of constants, of course. Using exceptions has other advantages, though: if one method fails, you could try another without re-entry, or print some post-mortem debugging info.