Regular LISTs have been implemented in such a way that the prev-pointer
does not point to the previous element, but to the next-pointer stored
in the previous element. This is done to simplify LIST_REMOVE(). This
macro can be implemented without knowing the address of the list head.
Unfortunately this makes it harder to implement LIST_PREV(), which is
why this macro was never here. Still, it is possible to implement this
macro. If the prev-pointer points to the list head, we return NULL.
Otherwise we simply subtract the offset of the prev-pointer within the
structure.
It's not as efficient as traversing forward of course, but in practice
it shouldn't be that bad. In almost all use cases, people will want to
compare the value returned by LIST_PREV() against NULL, so an optimizing
compiler will not emit code that does more branching than TAILQs.
While there, make the code a bit more readable by introducing
__member2struct(). This makes STAILQ_LAST() far more readable.
MFC after: 1 month
calling thread's unique integral ID, which is similar to AIX function of
the same name. Bump __FreeBSD_version to note its introduction.
Reviewed by: kib
Note: clock accepts CLOCK_VIRTUAL and CLOCK_PROF too, but this seems broken
as it simply waits for the difference of the current and given value of the
clock as if it were CLOCK_MONOTONIC. So document only CLOCK_REALTIME and
CLOCK_MONOTONIC as allowed.
MFC after: 1 week
Last year I added SLIST_REMOVE_NEXT and STAILQ_REMOVE_NEXT, to remove
entries behind an element in the list, using O(1) time. I recently
discovered NetBSD also has a similar macro, called SLIST_REMOVE_AFTER.
In my opinion this approach is a lot better:
- It doesn't have the unused first argument of the list pointer. I added
this, mainly because OpenBSD also had it.
- The _AFTER suffix makes a lot more sense, because it is related to
SLIST_INSERT_AFTER. _NEXT is only used to iterate through the list.
The reason why I want to rename this now, is to make sure we don't
release a major version with the badly named macros.
- Document the minor(3), major(3) and makedev(3) macro's. They also
apply to umajor() and uminor() in the kernel, but hopefully we'll sort
that out one day.
- Briefly dev2unit() inside the make_dev(9) manual page, since this is
now the preferred macro to obtain character device unit numbers inside
the kernel.
- Remove the device_ids(9) manual page. It contains highly inaccurate
information, such as a description of the nonexistent major().
Even though single linked lists allow items to be removed at constant time
(when the previous element is known), the queue macro's don't allow this.
Implement new REMOVE_NEXT() macro's. Because the REMOVE() macro's also
contain the same code, make it call REMOVE_NEXT().
The OpenBSD version of SLIST_REMOVE_NEXT() needs a reference to the list
head, even though it is unused. We'd better mimic this. The STAILQ version
also needs a reference to the list. This means the prototypes of both
macro's are the same.
Approved by: philip (mentor)
PR: kern/121117
the Open Group manpage for pthread_atfork(), available online at:
http://www.opengroup.org/onlinepubs/009695399/functions/pthread_atfork.html
which should be ok, since Daniel Eischen had mailed me about Open
Group manpages and the fact that they have granted permission to
FreeBSD to use their material. Any differences from the OG text are
my changes to the original manpage text submitted by Alex Vasylenko:
- In an effort to clean up the part that describes hooks and their
calling order, I used a list instead of a single paragraph for all the three
types of fork() hooks.
- After a short discussion with Dima Dorfman a long long time ago in a
far away galaxy, I changed the RETURN VALUES section to look more
like the rest of the pthread_xxx.3 manpages.
PR: docs/68201
Submitted by: Alex Vasylenko <lxv@omut.org>
to mistakes from day 1, it has always had semantics inconsistent with
SVR4 and its successors. In particular, given argument M:
- On Solaris and FreeBSD/{alpha,sparc64}, it clobbers the old flags
and *sets* the new flag word to M. (NetBSD, too?)
- On FreeBSD/{amd64,i386}, it *clears* the flags that are specified in M
and leaves the remaining flags unchanged (modulo a small bug on amd64.)
- On FreeBSD/ia64, it is not implemented.
There is no way to fix fpsetsticky() to DTRT for both old FreeBSD apps
and apps ported from other operating systems, so the best approach
seems to be to kill the function and fix any apps that break. I
couldn't find any ports that use it, and any such ports would already
be broken on FreeBSD/ia64 and Linux anyway.
By the way, the routine has always been undocumented in FreeBSD,
except for an MLINK to a manpage that doesn't describe it. This
manpage has stated since 5.3-RELEASE that the functions it describes
are deprecated, so that must mean that functions that it is *supposed*
to describe but doesn't are even *more* deprecated. ;-)
Note that fpresetsticky() has been retained on FreeBSD/i386. As far
as I can tell, no other operating systems or ports of FreeBSD
implement it, so there's nothing for it to be inconsistent with.
PR: 75862
Suggested by: bde
- Sort MAN and MLINKS in "dictionary" order ignoring case.
- For multi-value MAN and multi-pair MLINKS, put each value/pair
on its own line, for easier sorting and so that further diffs
are easier to see.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
