Another notable difference between POSIX threads and C++ threads is the simplicity of thread synchronization. Like the POSIX APIs, C++ provides the ability to create a mutex, as follows:
#include <mutex>#include <thread>#include <iostream>int count = 0;std::mutex mutex;void mythread(){ mutex.lock(); count++; mutex.unlock();}main(){ std::thread t1{mythread}; std::thread t2{mythread}; t1.join(); t2.join(); std::cout << "count: " << count << '\n';}// > g++ -std=c++17 scratchpad.cpp -lpthread; ./a.out// count: 2
In the preceding example, we create a thread that increments a shared counter, which is surrounded by a C++ std::mutex{}, in effect creating a guarded critical region. We then create two threads, wait for them to complete, ...
