Re: pthreads, cygwin and pthread_mutex_lock not blocking

[Peter Rehley <peter at rehley dot net>]

Any comments about this?

On Jun 2, 2005, at 11:22 AM, Peter Rehley wrote:

> Here is a patch to thread.cc that allows _lock to process signals.  
> The patch is against the 1.178 version of thread.cc found in cvs.
>
> --- thread.cc.orig      Thu Jun  2 11:17:39 2005
> +++ thread.cc   Thu Jun  2 11:20:00 2005
> @@ -1543,8 +1543,24 @@
>      }
>    else
>      {
> -      WaitForSingleObject (win32_obj_id, INFINITE);
> -      set_owner (self);
> +      //WaitForSingleObject (win32_obj_id, INFINITE);
> +      //set_owner (self);
> +      bool loop = true;
> +      do
> +       switch (pthread::cancelable_wait (win32_obj_id, INFINITE, 
> false, true))
> +         {
> +         case WAIT_OBJECT_0:
> +            set_owner (self);
> +            loop=false;
> +           break;
> +         case WAIT_SIGNALED:
> +           _my_tls.call_signal_handler ();
> +           break;
> +         default:
> +           // should never happen
> +           return EINVAL;
> +         }
> +      while (loop);
>      }
>
>    return result;
>
> On Jun 1, 2005, at 6:17 PM, Peter Rehley wrote:
>
> > Here is the patch to pthread.h
> >
> > hummingbird:~/MontaVista/tmp prehley$ diff -u pthread.h.cygwin 
> > pthread.h.new
> > --- pthread.h.cygwin    Wed Jun  1 18:15:40 2005
> > +++ pthread.h.new       Wed Jun  1 18:06:49 2005
> > @@ -53,12 +53,12 @@
> >  #define PTHREAD_MUTEX_RECURSIVE 0
> >  #define PTHREAD_MUTEX_ERRORCHECK 1
> >  #define PTHREAD_MUTEX_NORMAL 2
> > -#define PTHREAD_MUTEX_DEFAULT PTHREAD_MUTEX_ERRORCHECK
> > +#define PTHREAD_MUTEX_DEFAULT PTHREAD_MUTEX_NORMAL
> >  /* this should be too low to ever be a valid address */
> >  #define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP (pthread_mutex_t)18
> >  #define PTHREAD_NORMAL_MUTEX_INITIALIZER_NP (pthread_mutex_t)19
> >  #define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP (pthread_mutex_t)20
> > -#define PTHREAD_MUTEX_INITIALIZER 
> > PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
> > +#define PTHREAD_MUTEX_INITIALIZER PTHREAD_NORMAL_MUTEX_INITIALIZER_NP
> >  #define PTHREAD_ONCE_INIT { PTHREAD_MUTEX_INITIALIZER, 0 }
> >  #define PTHREAD_PRIO_INHERIT
> >  #define PTHREAD_PRIO_NONE
> > @@ -202,4 +202,3 @@
> >  #endif
> >
> >  #endif /* _PTHREAD_H */
> > -
> >
> > On Jun 1, 2005, at 5:22 PM, Peter Rehley wrote:
> >
> > > On May 31, 2005, at 10:50 AM, David Rothenberger wrote:
> > >
> > > > On 5/31/2005 10:15 AM, Peter Rehley wrote:
> > > > > Well, here is a simple test case, but turns out I wasn't using the 
> > > > > latest version.  I was having the problem on 1.5.12,  I haven't 
> > > > > been able to get a good build with cygwin 1.5.17-1.  It builds and 
> > > > > I can run the install script, but when I put the dll in place I 
> > > > > see the message "cygheap magic number mismatch detected", and gcc 
> > > > > doesn't want to work.
> > > >
> > > > I had a similar problem (see 
> > > > <http://cygwin.com/ml/cygwin/2005-05/msg01251.html>). It turned out 
> > > > it was because I was using the latest release of binutils. Try 
> > > > rolling back to the previous release.
> > > Ok, I rolled binutils to 20041229, rebuilt and copied the new dll.  
> > > It's having the same issue that I see in 1.5.12.  When I debug the 
> > > program, I see that the signal is being sent, but it doesn't get 
> > > executed.
> > >
> > > I've looked at the cygwin code, and I have noticed that the sleep 
> > > (nanosleep) is calling pthread::cancelable_wait, and that will call 
> > > WaitForMultipleObjects.  However, in pthread_mutex::_lock, it's only 
> > > using WaitForSingleObject.  I'm wondering if something like 
> > > WaitForMultipleObjects should be added to the lock function so that 
> > > signals (SIGCHLD, in my case) can be handled.
> > >
> > > It's just a guess since I'm not an expert with this code.
> > >
> > > Enjoy,
> > > Peter
> > > -------------------------------
> > > A Møøse once bit my sister
> > >
> > >
> > > --
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> > Enjoy,
> > Peter
> > -------------------------------
> > A Møøse once bit my sister
> >
> >
> > --
> > Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
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> Enjoy,
> Peter
> -------------------------------
> A Møøse once bit my sister
>
>
> --
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Enjoy,
Peter
-------------------------------
A Møøse once bit my sister


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