std::mutex
#include <iostream>
#include <map>
#include <string>
#include <chrono>
#include <thread>
#include <mutex>
std::map<std::string, std::string> g_pages;
std::mutex g_pages_mutex;
void save_page(const std::string &url)
{
// simulate a long page fetch
std::this_thread::sleep_for(std::chrono::seconds(2));
std::string result = "fake content";
std::lock_guard<std::mutex> guard(g_pages_mutex);
g_pages[url] = result;
}
int main()
{
std::thread t1(save_page, "http://foo");
std::thread t2(save_page, "http://bar");
t1.join();
t2.join();
// safe to access g_pages without lock now, as the threads are joined
for (const auto &pair : g_pages) {
std::cout << pair.first << " => " << pair.second << '\n';
}
}