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C++: Am I using this mutex correctly?
I feel that it can be done in a better way than this.
#include <functional>
#include <thread>
#include <mutex>
#include <chrono>
#include <iostream>
std::mutex m;
void f(int& n)
{
m.lock();
++n;
m.unlock();
std::this_thread::sleep_for( std::chrono::seconds(1) );
}
int main()
{
int n(0);
std::function<void()> h(std::bind(f, std::ref(n)));
std::thread f1(h);
f1.join();
std::this_thread::sleep_for( std::chrono::seconds(2) );
std::cout << n; // 1
}
Is this a correct way of using mutexes? I am new to this by the way.
1 Answer
- Anonymous8 years agoFavorite Answer
// Read this 8 PAGE tutorial
// http://www.justsoftwaresolutions.co.uk/threading/m...
//
// removed unneeded headers
#include <iostream>
#include <mutex>
#include <thread>
// internally linked mutex
static std::mutex m_n;
void f(int& n)
{
m_n.lock();
++n;
m_n.unlock();
std::this_thread::sleep_for(std::chrono::seconds(1));
}
// mutex released when scope is destroyed
void fs(int& n)
{
std::lock_guard <std::mutex> m(m_n);
++n;
}
int main()
{
int n(0);
std::thread t_f1(fs, std::ref(n));
std::thread t_f2(f, std::ref(n));
t_f1.join();
t_f2.join();
std::this_thread::sleep_for (std::chrono::seconds(2));
std::cout << n; // 1
}