Parameters fn A pointer to function, pointer to member, or any kind of move-constructible function object (i.e., an object whose class defines operator(), including closures and function objects). The return value (if any) is ignored. args... Arguments passed to the call to fn (if any). Their types shall be move-constructible. If fn is a member pointer, the first argument shall be an object for which that member is defined or a reference, or a pointer to it). x thread object whose state is moved to the constructed object.
// constructing threads
#include <iostream> // std::cout
#include <atomic> // std::atomic
#include <thread> // std::thread
#include <vector> // std::vector
std::atomic<int> global_counter (0);
void increase_global (int n) { for (int i=0; i<n; ++i) ++global_counter; }
void increase_reference (std::atomic<int>& variable, int n) { for (int i=0; i<n; ++i) ++variable; }
struct C : std::atomic<int> {
C() : std::atomic<int>(0) {}
void increase_member (int n) { for (int i=0; i<n; ++i) fetch_add(1); }
};
int main ()
{
std::vector<std::thread> threads;
std::cout << "increase global counter with 10 threads...\n";
for (int i=1; i<=10; ++i)
threads.push_back(std::thread(increase_global,1000));
std::cout << "increase counter (foo) with 10 threads using reference...\n";
std::atomic<int> foo(0);
for (int i=1; i<=10; ++i)
threads.push_back(std::thread(increase_reference,std::ref(foo),1000));
std::cout << "increase counter (bar) with 10 threads using member...\n";
C bar;
for (int i=1; i<=10; ++i)
threads.push_back(std::thread(&C::increase_member,std::ref(bar),1000));
std::cout << "synchronizing all threads...\n";
for (auto& th : threads) th.join();
std::cout << "global_counter: " << global_counter << '\n';
std::cout << "foo: " << foo << '\n';
std::cout << "bar: " << bar << '\n';
return 0;
}
std::thread 调用类的成员函数需要传递类的一个对象作为参数:
如果是在类的成员函数中处理thread,传入 this 即可,如:
参考:stackoverflow
参考C plus plus
类似这样
std::thread(&C::increase_member,std::ref(bar),1000)