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How to tell if I can open a file or not

Alex Martelli alex at magenta.com
Mon Jun 12 05:06:12 EDT 2000 
Donn Cave <donn at u.washington.edu> wrote in message
news:8hokva$2rqa$1 at nntp6.u.washington.edu...
    [snip]
> After you check, there's a period of time before you actually open
> the file.  It's a brief window, but it's real, and many things can
> happen in that time if the system is busy, including changes to the
> file's permission bits or even whether it exists.  Might as well
> just open the file, and if it works then you have a green light.

*EXACTLY*!!!  In the immortal words of Commodore Hopper:

    It's easier to get forgiveness than permission

I think she had another context in mind, but it works great for
the present one too: don't check if you're allowed to do X Y Z
(because things might change between your check and your doing
it), but rather, attempt to do the action ("just do it" comes to
mind:-) *AND*, of course, be ready to handle the exception ("get
forgiveness":-) if it turns out the action-attempt fails.


Alex
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