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
quotation. Also make sure we have the same amount of columns in each row as
the number of columns we specify in the head arguments.
Reviewed by: brueffer
This switches us to using -isoC-2011 as the symbol name which is used by
groff and mdocml. It follows the change to 4 digit years as done with
IEEE Std 1003 post-1999.
MFC after: 2 weeks (groff changes only)
The macro construction used now, is almost identical to the code
provided in C11 proposal N1404. This new version doesn't seem to
introduce any regressions according to the regression test in tools/,
but still seems to malfunction with Clang on certain aspects.
The new code does work successfully with GCC 4.2, 4.6 and 4.7. With 4.7,
it also works when __generic() is implemented on top of _Generic().
Discussed with: stefanf
As Garrett points out,
It is no more a debugging interface than setproctitle(3), and has not
been since the name started getting stuffed into the kernel. This
statement may have made sense when the name was only visible in thread
state dumps and the debugger.
PR: threads/158815
Submitted by: wollman@
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
Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.
Reviewed by: ru
Approved by: philip, ed (mentors)
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
