#include <iostream>
#include <boost/thread.hpp>
using std::endl; using std::cout;
using namespace boost;
mutex running_mutex;
struct dostuff
{
volatile bool running;
dostuff() : running(true) {}
void operator()(int x)
{
cout << "dostuff beginning " << x << endl;
this_thread::sleep(posix_time::seconds(2));
cout << "dostuff is done doing stuff" << endl;
mutex::scoped_lock running_lock(running_mutex);
running = false;
}
};
bool is_running(dostuff& doer)
{
mutex::scoped_lock running_lock(running_mutex);
return doer.running;
}
int main()
{
cout << "Begin.." << endl;
dostuff doer;
thread t(doer, 4);
if (is_running(doer)) cout << "Cool, it's running.\n";
this_thread::sleep(posix_time::seconds(3));
if (!is_running(doer)) cout << "Cool, it's done now.\n";
else cout << "still running? why\n"; // This happens! :(
return 0;
}
为什么上面程序的输出是:
开始..
酷,它正在运行。
dostuff 开始 4
dostuff 已完成 正在运行的东西
还在运行吗?为什么
dostuff 完成后如何正确标记?我不想坐等它,我只想在它完成时得到通知。