View mode: basic / threaded / horizontal-split · Log in · Help
April 06, 2009
Re: Thread pause and resume
Fawzi Mohamed wrote:
> On 2009-04-06 20:49:50 +0200, Steve Teale <steve.teale@britseyeview.com> 
> said:
> 
>> Steve Teale Wrote:
>>
>>> Sean Kelly Wrote:
>>>
>>>> == Quote from Steve Teale (steve.teale@britseyeview.com)'s article
>>>>>
>>>>> In some code I wrote at that time, I had a worker thread pool. When 
>>>>> a thread had done its job it would mark itself as available then
>>>> pause. The listener thread would then resume it or start one that 
>>>> had never been started. I'm trying to get it running in 2.26. There
>>>> are functions of the same name there but they are nested inside 
>>>> SuspendAll and ResumeAll, and so not accessible.
>>>>
>>>> This sounds like a classic producer/consumer case.  I suggest using 
>>>> condition
>>>> variables (core.sync.condition with core.sync.mutex).
>>>
>>> The problem is at the moment, that the D documentation covers the 
>>> language, and Phobos - the latter option exposes Object to some extent.
>>>
>>> Anything that is in core.* is undocumented and you have to 'rtfsc' - 
>>> if you can find it. I can't even find "core.sync" in D files under 
>>> dmd. Can you point me in the right direction please.
>>>
>>> Thanks Steve
>>>
>> As an aside, I realize that Thread.suspend is dodgy, it's been 
>> deprecated in Java and C#. Can the metaprogrammers out there come up 
>> with a way to insist that a particular member function is called only 
>> from the instance that it 'belongs' to. Then presumably it could be 
>> made safe.
> 
> no pause and resume remains a bad idea because [...]

    ^

Insert comma here.


Andrei
April 07, 2009
Re: Thread pause and resume
On Mon, 06 Apr 2009 10:14:41 -0400, Steve Teale  
<steve.teale@britseyeview.com> wrote:

> Robert Jacques Wrote:
>
>> On Mon, 06 Apr 2009 05:57:24 -0400, Steve Teale
>> <steve.teale@britseyeview.com> wrote:
>>
>> > Earlier versions of D2.x used std.thread which had pause() and  
>> resume().
>> > The later versions use core.thread where these appear to be missing.
>> >
>> > Any portable workaround suggestions?
>> >
>>
>> Also, these functions (if you dig into their implementation) are
>> documented as being for debuggers and/or GCs only. Specifically, they  
>> can
>> not be used for synchronization, etc.
>
> In 2.06 they were just:
>
>     /**
>      * Suspend execution of this thread.
>      */
>     void pause()
>     {
> 	if (state != TS.RUNNING || SuspendThread(hdl) == 0xFFFFFFFF)
> 	    error("cannot pause");
>     }
>
>     /**
>      * Resume execution of this thread.
>      */
>     void resume()
>     {
> 	if (state != TS.RUNNING || ResumeThread(hdl) == 0xFFFFFFFF)
> 	    error("cannot resume");
>     }
>
> No prohibitions or warnings.

Okay, now follow SuspendThread and ResumeThread and you'll eventually run  
into a (on windows) a function call which is documented on MSDN with a  
bunch of warnings. Admittedly, I traced this a while ago, so pause and  
resume might have been re-purposed away from GC use, but this used to be  
the case.
Next ›   Last »
1 2
Top | Discussion index | About this forum | D home