synchronized (this[.classinfo]) in druntime and phobos

[deadalnix]

Le 31/05/2012 11:55, Regan Heath a écrit :
> On Thu, 31 May 2012 10:48:51 +0100, Andrei Alexandrescu
> <SeeWebsiteForEmail at erdani.org> wrote:
>
>> On 5/31/12 2:36 AM, Regan Heath wrote:
>>> On Wed, 30 May 2012 19:29:39 +0100, Andrei Alexandrescu
>>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>> You can have deadlocks but with synchronized you can't leak locks or
>>>> doubly-unlock them. With free mutexes you have all of the above.
>>>
>>> I'm not suggesting using free mutexes. I'm suggesting keeping the mutex
>>> private inside the object.
>>
>> Ergo, you are suggesting using free mutexes. Your second sentence
>> destroys the first.
>
> Depends on your definition of "free". You appear to have meant as an
> instance/pointer/object even one in a class, I initially read it as
> meaning as a separate object from the class you're locking. In any case,
> you're right the compiler doesn't get synchronized()
> statements/classes/methods wrong and a programmer can. The trade-off is
> the cause of this thread of discussion.
>
> R
>

I think you misunderstand each other. Here is what I nderstand :

Andrei is talking about free mutex in the sense of a mutex with lock and 
unlock function available. Such a mutex is error prone, because you can 
lock/unlock in an incorrect way.

synchronized is here a better alternative, because lock and unlock 
always goes by pair.

Regan, by free mutex, you mean a mutex that can be locked and unlocked 
by everybody. This is problematic too.

The ideal is to lock in a way that isn't a free mutex in both definition 
of the term.