synchronized { }

[Bruno Medeiros]

Sean Kelly wrote:
> == Quote from Sean Kelly (sean at invisibleduck.org)'s article
>> == Quote from torhu (no at spam.invalid)'s article
>>> Sean Kelly wrote:
>>>> == Quote from Graham St Jack (graham.stjack at internode.on.net)'s article
>>>>> On Thu, 26 Jun 2008 08:15:24 -0400, Michel Fortin wrote:
>>>>>> On 2008-06-25 21:18:41 -0400, Walter Bright <newshound1 at digitalmars.com>
>>>>>> said:
>>>>>>
>>>>>>> Right now, if you use a synchronized statement with no argument, it
>>>>>>> will sync on a mutex unique to that statement.
>>>>>>>
>>>>>>> Does anyone write threading code that depends on this behavior?
>>>>>> I've used it before, thinking it was equivalent to synchronize(this) {},
>>>>>> an incorrect assumption obviously. If you get rid of it, I won't miss
>>>>>> it.
>>>>> Same.
>>>> Um, it /is/ equivalent to synchronized(this).  What made you think differently?
>>>>
>>> Don't the docs say that they're not equivalent?
>>> http://www.digitalmars.com/d/2.0/statement.html#SynchronizedStatement
>>> I thought they were the same too, before Walter checked in something to
>>> phobos that made me think otherwise.  Can't remember what exactly.
>> They're identical, unless something changed recently in D 2.0.  Walter confirmed
>> this explicitly for me a while back, though I don't have a link handy.
> 
> I was finally inspired to track down the reference for this statement:
> 
> http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D.bugs&artnum=5268
> http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D.bugs&artnum=5276
> 
> The second post from Walter is a reply to my post in the first link.  Given
> this, I can only assume that Walter either misunderstood me or that the behavior
> was changed silently at some point--I'm pretty sure the latter since I tested
> this way back when.  In any case, the current behavior is as Walter described,
> and I consider it utterly broken.  Not only is it inconsistent with Java, which
> is what I believe this design was based on, but it's completely useless in the
> general case.  It has to change, but I really wish that the behavior could be
> fixed in D 1.0 as well.  Not likely I know, but oh well.
> 
> 
> Sean

What do you mean inconsistent with Java? I checked it out now, and 
apparently Java does not have a synchronized statement with no arguments 
(http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.19).

Why is the current behavior broken?

-- 
Bruno Medeiros - Software Developer, MSc. in CS/E graduate
http://www.prowiki.org/wiki4d/wiki.cgi?BrunoMedeiros#D