将2个指针传递给2个线程,但它们最终共享相同的内容

我想这个问题已经出现了,它肯定会在线程世界中显示我的初学者级别,但我无法找到任何先前的问题或其他资源来解决它.我已经完成了对C++ 11线程最常见的介绍(比如这个,这个和这个),但它没有帮助.

这是我的代码:

mutex mtx;
vector threads;

for(vcit = vc.begin(); vcit != vc.end(); ++vcit) {
    const std::shared_ptr g = graphs.at(*vcit);

    cout << "Graph (outside thread): " << g->name << endl;
    threads.push_back(thread(
        [&g, &mtx] () {
            lock_guard guard(mtx);
            cout << "Graph (inside thread): " << g->name << endl;
        }
    ));
}

for(thread& t : threads) {
    t.join();
} 

Graph (outside thread): ABC
Graph (outside thread): DEF
Graph (inside thread): DEF
Graph (inside thread): DEF

Graph (outside thread): ABC
Graph (inside thread): ABC
Graph (outside thread): DEF
Graph (inside thread): DEF