A monitor for every object

[Sean Kelly]

Steven Schveighoffer Wrote:

> On Fri, 04 Feb 2011 18:29:08 -0500, Sean Kelly <sean at invisibleduck.org>  
> wrote:
> 
> > On Feb 4, 2011, at 3:06 PM, Tomek Sowiński wrote:
> >
> >> Steven Schveighoffer napisał:
> >>
> >>> D also allows you to replace it's monitor with a custom monitor object
> >>> (i.e. core.sync.Mutex) so you can have more control over the mutex,  
> >>> assign
> >>> the same mutex to multiple objects, use conditions, etc.  It's much  
> >>> more
> >>> flexible than Java or C# IMO.
> >>
> >> I didn't know, thx. Where is it documented?
> >
> > Only in the docs for the Mutex ctor here:
> >
> > http://www.digitalmars.com/d/2.0/phobos/core_sync_mutex.html
> >
> > By the way, when using Mutex as an object monitor you currently can't  
> > attach dispose event handlers to the object (ie. via std.signals).  That  
> > functionality is only supported by the default monitor.  I've considered  
> > changing this, but doing so imposes some weird requirements on the  
> > creators of an external object monitor, like Mutex.
> 
> Sean, I could have sworn that mutex can take over multiple objects'  
> monitors.  This would be highly desirable in a complex structure where  
> members of an object should use the same mutex for synchronized calls.
> 
> But looking at the docs once again, it looks like it can only be the  
> monitor for one object (as the target object is accepted only on  
> construction).  Is that a limitation we cannot remove?

Now that you mention it, I think TDPL describes a call like setMonitor() that's supposed to do this, and I just forgot to implement it.  There's no technical barrier.  It's simply a matter of assigning the monitor reference to the correct part of the Mutex instance.