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Re: S_IFMT not mentioned in any man page
Mouse <mouse%Rodents-Montreal.ORG@localhost> wrote:
|>>> instead of at some S_FILETYPE(struct stat) or whatever, restricting
|>>> the scope of system library implementors.
|>> It's not much of a restriction; IMO it is outweighed by the things
|>> it allows on the caller side of the API.
|Actually, providing something like S_FILETYPE() to do what
|st_mode&S_IFMT now does would give most of the benefit. (Would have
|given, actually, since there is now a huge installed base to consider.)
|Probably me misreading; I initially read you as advocating providing
|only the various S_ISxxx() test macros.
No, i was not. I showed understanding for POSIX doing so for
future code for encapsulation purposes. On the hand, since you
need to pass st_mode...
|> Well you are not free to choose where and how the mode bits are
|> stored, they have to be in the single field st_mode or what and must
|> be diggable with a simple mask.
|Yes, but only at the API. Nothing says they have to be stored together
|on disk - indeed, nothing says they have to be stored at all, if they
|can be derived from something else. And, no matter what your
|S_FILETYPE() looks like, every filesystem implementation would have to
|conform to it, so you really wouldn't've gained much.
Yes all that can or has to be assembled anyway. And with a 64-bit
st_mode it seems even cloud-services can be expressed as
|> How can it be outweighed?
|By supporting direct switch() on the type. (As I said, I (mis)read
|what you wrote....)
Yep (to the first part).
|> Well i'm all for freedom but that also means freedom of implementors,
|> here they have deal with a very hard and complicated task. Just
|> recall all that struct stat mess, with stat64 etc.
|What's stat64? I just did a search through /sys on my most recent
|NetBSD rev (5.2) and the only occurrences of "stat64" I found anywhere
|were in compat/.
Oh don't ask me, this is a mishmash from header files i have ever
seen. Add "ostat" or something similar. If you argue against
POSIX then it is not fair to only look into NetBSD /usr/include,
|> A S_FILETYPE(struct stat) would make sense in my opinion,
|Perhaps, but I don't see it as having much benefit over the existing
|scheme (especially in view of the installed base). All filesystem
|implementations would still have to generate the same data structure,
|whether it consisted of today's st_mode or not.
True, as above. It was just a mapping of what i had in C++,
something that i as a Unix newcomer thought after Y 2000. I.e.,
i did actually not end up with the same or a similar scheme, which
i thought being possibly interesting. So that is me, i do
understand that POSIX wants to move, but i don't like the
remaining approach either (since it lands on st_mode instead of
simply taking struct stat*). On the other hand it is fascinating
that even today st_mode/m_ino/st_dev/st_rdev are sufficient to
express the file world (the latter three being Unix only)!
Oh You Pretty Things!
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