cvs commit: src/share/man/man9 Makefile condvar.9 lock.9
mi_switch.9 mtx_pool.9 mutex.9 rwlock.9 sleep.9 sleepqueue.9
sx.9 thread_exit.9 src/sys/kern kern_synch.c src/sys/sys
mutex.h rwlock.h sleepqueue.h sx.h systm.h
Pawel Jakub Dawidek
pjd at FreeBSD.org
Mon Mar 12 20:03:54 UTC 2007
On Mon, Mar 12, 2007 at 03:35:21PM -0400, John Baldwin wrote:
> On Monday 12 March 2007 14:56, Pawel Jakub Dawidek wrote:
> > On Mon, Mar 12, 2007 at 11:16:23AM -0400, John Baldwin wrote:
> > > On Saturday 10 March 2007 15:52, Pawel Jakub Dawidek wrote:
> > > > What about something like this:
> > > >
> > > > #define cv_wait(cv, lock) do {
> > > > switch (LO_CLASSINDEX((struct lock_object *)(lock))) {
> > >
> > > The problem with a cast is you use type checking. Might as well do this:
> > >
> > > #define cv_wait(cv, lock) _cv_wait((cv), (struct lock_object *)(lock))
> >
> > This will skip type checking and my version only cast to provide type
> > checking, so when you pass some random variable it will give you an
> > error.
>
> Not really, you may pass some garbage and the LO_CLASSINDEX turns out to be a
> mutex. :) You only get a runtime error, not a compile-time one.
> Type-checking by the compiler is nice because you get compile-time errors.
I'll get compile-time error, because cv_wait_mtx() takes
'struct condvar *' and 'struct mtx *' as arguments. So even if some
garbage returns 1, which turns out to be a mutex, call to cv_wait_mtx()
will generate compile-time error.
But it seems the solution may not be that good if it is not very obvious
on a first look. If typeof() thing works, its fine by me, just give me
condvar(9) that works with sx(9) locks:)
--
Pawel Jakub Dawidek http://www.wheel.pl
pjd at FreeBSD.org http://www.FreeBSD.org
FreeBSD committer Am I Evil? Yes, I Am!
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/cvs-src/attachments/20070312/7eec9045/attachment.pgp
More information about the cvs-src
mailing list