CODEWITHSUNDEEP
c++multithreadingthread-safetypthreadsmultiple-instances
DikotaLolly
DikotaLolly

Reputation: 47

Thread safety for multiple instance of object and multithreading

I want to each of these 3 object instance run in parallel. I have no global variables. Is it thread-safe? or do i need some syncronization mechanism?

class myClass{
public:
    myClass();
    ~myClass();
    void myFunction();
}

int main() {
    myClass myObj1, myObj2, myObj3;
    pthread_t myThread1, myThread2, myThread3;

    pthread_create(&myThread1, NULL, myObj1::myFunction, NULL );
    pthread_create(&myThread2, NULL, myObj2::myFunction, NULL );
    pthread_create(&myThread3, NULL, myObj3::myFunction, NULL );
    ...
}

Could you explain me why or why not need for syncronization?

EDIT: In the below, some friends say that this program cannot compile because while creating pthread i used non-static member function call. I just wanted to show what is my problem here. For Friends who want to use non-static member function with pthreads, its my code;

struct thread_args{
    myClass* itsInctance;
    //int i,j,k; // also if you want to pass parameter to function you use in 
    //pthread_create u can add them here
}

void* myThread(void* args){
    thread_args *itsArgs = (thread_args*)args;
    itsArgs->itsInstance->myFunciton();
}

int main() {
    myClass myObj1;
    pthread_t myThread1;

    thread_args itsArgs;
    itsArgs.itsInstance = &myObj1;
    // also if you have any other params, fill them here

    pthread_create(&myThread1, NULL, myThread, &itsArgs);
        ...
    }

Upvotes: 1

Views: 281

Answers (1)

Maxim Egorushkin
Maxim Egorushkin

Reputation: 136515

Could you explain me why or why not need for syncronization?

You need synchronization when there is a data race.

Since in your example there is no data, there cannot be a data race.

You may find video Plain Threads are the GOTO of todays computing - Hartmut Kaiser - Keynote Meeting C++ 2014 instructive.

Upvotes: 1

Related Questions