On 01Sep2015 11:56, random...@fastmail.us <random...@fastmail.us> wrote:
On Tue, Sep 1, 2015, at 10:57, Steven D'Aprano wrote:
Q3: I could probably answer Q2 myself if I knew how to check whether a
fd
was open or not. With a file object, I can inspect file_obj.closed and it
will tell me whether the file is open or not. Is there an equivalent for
file descriptors?
Well, if you try to call os.close, or any other operation for that
matter, it will raise an OSError with errno=EBADF.
os.fstat might be safer. It won't have side effects.
As additional remarks:
Underwhat circumstances would you imagine probing an fd like this? For what
purpose? It feels like a code smell for know having enough situational
awareness, and then you're into guesswork world.
One circumstance where you might use fdopen and _not_ want .close to close the
underlying service is when you're handed a file descriptor over which you're
supposed to perform some I/O, and the I/O library functions use high level
files. In that case you might want code like this:
fd2 = os.dup(fd)
fp = open(fd2, 'a+b') # or whatever mode
... do stuff, perhaps passing fp to a library function ...
fp.close()
fd2 is not closed, but fd is still open for further use.
Cheers,
Cameron Simpson <c...@zip.com.au>
This is not a bug. It's just the way it works, and makes perfect sense.
- Tom Christiansen <tchr...@jhereg.perl.com>
I like that line. I hope my boss falls for it.
- Chaim Frenkel <cha...@cris.com>
--
https://mail.python.org/mailman/listinfo/python-list
