One for experts in std.parallelism

[Andrei Alexandrescu via Digitalmars-d]

On 06/12/2017 12:13 AM, Stanislav Blinov wrote:
> On Sunday, 11 June 2017 at 19:06:48 UTC, Andrei Alexandrescu wrote:
>> I tried to eliminate the static shared ~this as follows:
>>
>> https://github.com/dlang/phobos/pull/5470/commits/a4b2323f035b663727349d390719509d0e3247ba 
>>
>>
>> However, unittesting fails at src/core/thread.d(2042). I suspect it's 
>> because the atexit call occurs too late, after the shared static this 
>> in src/core/thread.d has already been called.
>>
>> Thoughts on how to make this work?
>>
>>
>> Thanks,
>>
>> Andrei
> 
> Which atexit call? The shared static ~this is still present in that commit.

Eh, the link doesn't work anymore; I hoped it would be immutable. 
Anyhow, I just tried this again:

private final class ParallelismThread : Thread
{
     this(void delegate() dg)
     {
         super(dg);
         static shared bool once;
         import std.concurrency;
         initOnce!once({
             import core.stdc.stdlib;
             atexit(&doThisAtExit);
             return true;
         }());
     }

     TaskPool pool;
}

// Kill daemon threads.
//shared static ~this()
extern(C) void doThisAtExit()
{
     foreach (ref thread; Thread)
     {
         auto pthread = cast(ParallelismThread) thread;
         if (pthread is null) continue;
         auto pool = pthread.pool;
         if (!pool.isDaemon) continue;
         pool.stop();
         pthread.join();
     }
}

There's no more shared static ~this(). Instead, we have an atexit 
registration. It fails in src/core/thread.d(2042).


Andrei