Hi,
In Python, and in general - does a close() operation on a file object imply a flush() operation?
Adam
views:
293answers:
2
+2
A:
Yes. It uses the underlying close() function which does that for you. Source here.
Martin Wickman
2010-03-15 12:50:59
(In other words: That file I/O is buffered is large abstracted and hidden away from you. Doing an `open`, `write`, `close` shouldn't leave stuff unwritten as that's what you already intended with `write`. A buffer that routinely eats what gets thrown at it would be quite a bad design [or a hungry buffer].)
Joey
2010-03-15 12:54:03
Thanks, that was my guess too. But is this true cross-platform, cross-OS, and cross-languages?
Adam Matan
2010-03-15 12:57:34
@Adam Matan: That's why Python sits on top of the C libraries. To assure that "this true cross-platform, cross-OS". I don't know what "cross-languages" means.
S.Lott
2010-03-15 13:18:52
+1 Thanks. By "cross-language" I meant to ask whether this behavior is similar in the vast majority of modern programming languages.
Adam Matan
2010-03-15 15:25:29
+2
A:
NB: close() and flush() won't ensure that the data is actually secure on the disk. It just ensures that the OS has the data == that it isn't buffered inside the process.
You can try sync or fsync to get the data written to the disk.
Douglas Leeder
2010-03-15 12:57:18
True, but doesn't modern OS write the data to the disk upon process termination?
Adam Matan
2010-03-15 13:55:07
Depends on the time scales you are talking about. e.g. some versions of ext4 might wait whole seconds before committing your data to the disc.
Douglas Leeder
2010-03-15 14:44:31