Re: std::thread...too little, too late?

From:
Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>
Newsgroups:
comp.lang.c++
Date:
Thu, 18 Dec 2014 21:05:42 +0000
Message-ID:
<mKKdnSPsl_kG3A7JnZ2dnUU7-bmdnZ2d@giganews.com>
On 18/12/2014 11:36, me wrote:

I was looking at what made its way into the C++11 standard in the way of
threads, and it seems very braindead. I mean third party libraries have
been giving us working threading for years, and "THAT"was all they came
up with for the standard?

I fully understand the implications of adding features that need to be
portable and that give a good least common denominator, but std::thread
seems too little, too late.

I thought it would be easy to at least build upon the std::thread class
and to something that more closely resembles the common threading utility
available in a variety of libraries: something with delayed thread
starting, and the ability to make the process OO with a virtual run()
method...no such luck.

Consider the following example that uses std::thread as a class trait and
then subclasses a UsefulThread class, adding the requested functionality:

class UsefulThread {
     thread* stdThread;
public:
     UsefulThread();
     virtual ~UsefulThread() { delete stdThread; }
     virtual void run()=0;
     void start() { stdThread=new thread(run); }
     void join() { stdThread->join(); }
};

class WorkerThread: public UsefulThread {
     int _id;
     BufferObject& r;
public:
     WorkerThread(int id, BufferObject& b): UsefulThread(), _id(id), r(b)
{}
     virtual void run() { for (auto i=0; i<_id; i++) r << _id; }
         // share r object is made threadsafe with an internal mutex
};

int main(int argc, char** argv) {
     using namespace std;
     list<int> v ={1, 2, 3, 4, 5, 6, 7, 8, 9};
     BufferObject b;
     list<WorkerThread> threadList;
     for (auto i: v) { WorkerThread t(i, b); threadList.push_back(t); };
     for (auto i: threadList) i.start();
     for (auto i: threadList) i.join();

     cout << b.str() << endl;

     return 0;
}

There is no way (that I can tell of) to make the UsefulThread::start()
method properly register the run() virtual. There was an article online


Stop fucking moaning mate.

void start() { stdThread=new thread(std::bind(&UsefulThread::run, this)); }

/Flibble

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