POST 1 : std::thread in c++ | C++ 11

std::thread
 

C++  Thread support library std::thread. Threads enable programs to execute across several processor cores.


Defined in header

Class :
thread

Member types :
native_handle_type


Data Member 
id    //represents the id of a thread (public member class)


Member functions

(constructor)   //constructs new thread object (public member function)

(destructor)    //destructs the thread object, underlying thread must be joined or detached  (public member function)

operator=    //moves the thread object 

Observers  // Covered in NEXT POST

Operations   // Covered in NEXT POST

Constructor :  

#include 
 
void f1(int n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread 1 executing\n";
        ++n;
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}
 
void f2(int& n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread 2 executing\n";
        ++n;
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}
 
int main()
{
    int n = 0;
    std::thread t1; // t1 is not a thread
    std::thread t2(f1, n + 1); // pass by value
    std::thread t3(f2, std::ref(n)); // pass by reference
    std::thread t4(std::move(t3)); // t4 is now running f2(). t3 is no longer a thread
    t2.join();
    t4.join();
    std::cout << "Final value of n is " << n << '\n';
}

DON't WORRY ABOUT OUTPUT AT THIS STAGE

Destructor:  

~thread();		(since C++11)

Destroys the thread object.

If *this has an associated thread (joinable() == true), std::terminate() is called.

std::thread::operator= :
 
C++  Thread support library std::thread

thread& operator=( thread&& other ) noexcept;

(since C++11)
If *this still has an associated running thread (i.e. joinable() == true), call std::terminate(). Otherwise, assigns the state of other to *this and sets other to a default constructed state.

After this call, this->get_id() is equal to the value of other.get_id() prior to the call, and other no longer represents a thread of execution.

• Parameters :

other - another thread object to assign to this thread object

• Return value :

*this