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RE: read/write locks
- To: "Medina, Aurelio" <aureliom@crt.com>
- Subject: RE: read/write locks
- From: Ross Johnson <rpj@ise.canberra.edu.au>
- Date: Fri, 10 Sep 1999 15:19:43 +1000 (EST)
- cc: Pthreads Developers List <pthreads-win32@sourceware.cygnus.com>
Hi,
Re the read/write lock routines, I'll see if I can get them into the
next snapshot, but it may be the one after so that I don't delay
too long in getting recent bug fixes into the DLL.
Ross
On Thu, 9 Sep 1999, Medina, Aurelio wrote:
> To all,
>
> Speaking of read/write locks, does anyone know if the POSIX read/write lock
> routines (e.g. pthread_rwlock_init()) that I submitted will eventually
> become part of the Pthreads-Win32 library? Seems like someone is already
> working on another implementation. The routines that I submitted were
> introduced in UNIX98 and are currently a X/Open standard. These routines
> are portable and are currently available on HP-UX 11.0.
>
> Thanks,
> Aurelio Medina
>
> -----Original Message-----
> From: Mikael.Ambrus@elema.siemens.se
> [SMTP:Mikael.Ambrus@elema.siemens.se]
> Sent: Thursday, September 09, 1999 10:47 AM
> To: pthreads-win32@sourceware.cygnus.com
> Subject: pthread_cond_timedwait
>
> [Ambrus Mikael] Dear pthreads colleagues,
>
> I'm writing a program that uses pthread_cond_timedwait. In
> the book
> that I'm using (Pthreads Programming by Nicols, Buttlar & Proulux
> Farell )
> it says that this function should suspend the thread until some
> other thread
> calls pthread_cond_signal, pthread_cond_broadcast OR the system
> timer is
> greater than or equal to the third argument (abstime).
>
> Since clock_gettime is not implemented and I cant find some
> other
> function that tells me the system time, I've tried to implement my
> own
> version of clock_gettime by using the ansi function clock(). This
> function
> returns the number of ticks that has elapsed since the program was
> started.
>
> But it seams that this is not the same absolute time that
> pthread_cond_timedwait requires since the thread won't awaken.
>
> Is there another way to acquire the relevant system time?
>
> Another thing that has bothered me is that I recently
> downloaded the
> latest snip of phtreads and now my read/write locks won't work.
> Since the
> precompiled lib isn't recognised by the linker (neither with gcc
> v20.1 nor
> MSVC 6.0) for some reason, I built the libs using the buildlib.bat
> provided.
> Here's a snip of the code that fails:
>
> int pthread_rdwr_wunlock_np (
> pthread_rdwr_t *rdwrp
> ){
> assert( pthread_mutex_lock(&(rdwrp->mutex)) == 0 );
> if (rdwrp->writers_writing == 0) {
> assert( pthread_mutex_unlock(&(rdwrp->mutex)) == 0 );
> return(-1);
> }else{
> rdwrp->writers_writing = 0;
> assert(pthread_cond_broadcast(&(rdwrp->lock_free)) ==
> 0);
>
> };
>
> assert( pthread_mutex_unlock(&(rdwrp->mutex)) == 0 );
> return(0);
> };
>
> pthread_cond_broadcast returns EINVAL. Does anyone recognise
> this
> problem?
>
> Wkr
> Michael Ambrus
> Siemens Elema
> >
>
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