Trying to develop a pool executor from pthreads... in C++

Trying to develop a pool executor from pthreads... in C++

[mlnglstaccram alksjd]

For the sake of learning i am trying to develp a pool executor... but
it doesnt work.. can u ppl tell me where i am goin wrong? I am getting
an assertion failure in windows in the line below with comments, in
file PoolExecutor.h..


/*
main.cpp
*/
#include <pthread.h>
#include <iostream>
#include <windows.h>
#include "PoolExecutor.h"



using namespace std;

class Runner{
public:
       Runner(){}
       ~Runner(){}
       void run(){
               for(int i=0;i<100;++i)
                       cout<<"i="<<i << " in thread "<<
((int)pthread_self().p) <<endl;
       }
};

int main(){
       PoolExecutor pool(10);
       pool.execute(((Runnable *)new Runner()));
       pool.execute(((Runnable *)new Runner()));
       pool.execute(((Runnable *)new Runner()));
       Sleep(1000);
       return 0;
}

///////////////////////////////////////////////////////////////////////////next
file//////////////////////////////////////////

/*in file PoolExecutor.h*/

#include<pthread.h>
#include<queue>
#include<windows.h>

class PoolExecutor;
void *func(void *temp);

class Runnable{
public:
       virtual void run()=0;
};


class Thread{
       pthread_t threadId;
       Runnable *runnable;
public:
       Thread(){
               runnable=NULL;
       }

       void start(PoolExecutor *pthRun){
               int started = pthread_create (&threadId, NULL, func, pthRun);
               std::cout<< started<<std::endl;
       }

       void join(){
               pthread_join(threadId,NULL);
       }

};



class PoolExecutor{
       Thread *threads;
       int N;
       bool cancelled ;
       std::queue<Runnable*> taskQueue;
       pthread_mutex_t taskQueueMutex;
public:
       PoolExecutor(int numberOfThreads){
               N=numberOfThreads;
               if(numberOfThreads<=0 && numberOfThreads>512)
                       N=5;
               cancelled= false;
       pthread_mutex_init(&taskQueueMutex,NULL);
               threads = new Thread[N];
               for(int i=0;i<N;++i)
                       threads[i].start(this);
       }
       ~PoolExecutor(){
               cancelled = true;
               for(int i=0;i<N;++i)
                       threads[i].join();
               delete[] threads;
       }

       void execute(Runnable* runnable ){
               pthread_mutex_lock(&taskQueueMutex);
               taskQueue.push(runnable);
               pthread_mutex_unlock(&taskQueueMutex);
       }

       void* runMethod(void * param){
               for(;;){
                       while(taskQueue.empty()&& !cancelled){
                               Sleep(100);
                       }
                       if(cancelled){
                               return NULL;
                       }
                       pthread_mutex_lock(&taskQueueMutex);
                       if(taskQueue.empty()){
                               pthread_mutex_unlock(&taskQueueMutex);
                               continue;
                       }
                       Runnable *runnable = (Runnable *)taskQueue.front();
////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////// i get error in the above line
////////////////////////////////////////////////////////////////////////////////////////////////
                       taskQueue.pop();
                       pthread_mutex_unlock(&taskQueueMutex);
                       runnable->run();
                       delete runnable;
                       if(cancelled){
                               return NULL;
                       }
               }
               return NULL;
       }

};

void *func(void *temp){
       PoolExecutor *poolExecutor = (PoolExecutor *)temp;
       return poolExecutor->runMethod(NULL);
}

Thanks

Re: Trying to develop a pool executor from pthreads... in C++

[gcherian]

Hello,

Runner class should be inheriting the Runnable (to override the virtual
run() method)

-George Cherian


mlnglstaccram alksjd wrote:
> 
> For the sake of learning i am trying to develp a pool executor... but
> it doesnt work.. can u ppl tell me where i am goin wrong? I am getting
> an assertion failure in windows in the line below with comments, in
> file PoolExecutor.h..
> 
> 
> /*
> main.cpp
> */
> #include <pthread.h>
> #include <iostream>
> #include <windows.h>
> #include "PoolExecutor.h"
> 
> 
> 
> using namespace std;
> 
> class Runner{
> public:
>        Runner(){}
>        ~Runner(){}
>        void run(){
>                for(int i=0;i<100;++i)
>                        cout<<"i="<
> #include<queue>
> #include<windows.h>
> 
> class PoolExecutor;
> void *func(void *temp);
> 
> class Runnable{
> public:
>        virtual void run()=0;
> };
> 
> 
> class Thread{
>        pthread_t threadId;
>        Runnable *runnable;
> public:
>        Thread(){
>                runnable=NULL;
>        }
> 
>        void start(PoolExecutor *pthRun){
>                int started = pthread_create (&threadId, NULL, func,
> pthRun);
>                std::cout<< started<<std::endl;
>        }
> 
>        void join(){
>                pthread_join(threadId,NULL);
>        }
> 
> };
> 
> 
> 
> class PoolExecutor{
>        Thread *threads;
>        int N;
>        bool cancelled ;
>        std::queue<Runnable*> taskQueue;
>        pthread_mutex_t taskQueueMutex;
> public:
>        PoolExecutor(int numberOfThreads){
>                N=numberOfThreads;
>                if(numberOfThreads<=0 && numberOfThreads>512)
>                        N=5;
>                cancelled= false;
>        pthread_mutex_init(&taskQueueMutex,NULL);
>                threads = new Thread[N];
>                for(int i=0;i<N;++i)
>                        threads[i].start(this);
>        }
>        ~PoolExecutor(){
>                cancelled = true;
>                for(int i=0;i<N;++i)
>                        threads[i].join();
>                delete[] threads;
>        }
> 
>        void execute(Runnable* runnable ){
>                pthread_mutex_lock(&taskQueueMutex);
>                taskQueue.push(runnable);
>                pthread_mutex_unlock(&taskQueueMutex);
>        }
> 
>        void* runMethod(void * param){
>                for(;;){
>                        while(taskQueue.empty()&& !cancelled){
>                                Sleep(100);
>                        }
>                        if(cancelled){
>                                return NULL;
>                        }
>                        pthread_mutex_lock(&taskQueueMutex);
>                        if(taskQueue.empty()){
>                                pthread_mutex_unlock(&taskQueueMutex);
>                                continue;
>                        }
>                        Runnable *runnable = (Runnable *)taskQueue.front();
> ////////////////////////////////////////////////////////////////////////////////////////////////
> //////////////////////////////////// i get error in the above line
> ////////////////////////////////////////////////////////////////////////////////////////////////
>                        taskQueue.pop();
>                        pthread_mutex_unlock(&taskQueueMutex);
>                        runnable->run();
>                        delete runnable;
>                        if(cancelled){
>                                return NULL;
>                        }
>                }
>                return NULL;
>        }
> 
> };
> 
> void *func(void *temp){
>        PoolExecutor *poolExecutor = (PoolExecutor *)temp;
>        return poolExecutor->runMethod(NULL);
> }
> 
> Thanks
> 
> 

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