[英]Using asynchronous boost asio code for synchronous operation
我有一个用boost ASIO编写的服务器和客户端代码,它工作得很好。 由于同步和异步boost asio API的不同,因此我为异步通信编写的代码是否有可能以同步方式而不是异步的方式工作和工作。 ?
您可以在专用的io_service上运行任何异步代码,并且只需运行服务阻止:
#include <boost/asio.hpp>
#include <boost/asio/high_resolution_timer.hpp>
#include <iostream>
using namespace std::chrono_literals;
using namespace boost::asio;
using boost::system::system_error;
io_service svc;
high_resolution_timer deadline(svc, 3s);
void task_foo() {
deadline.async_wait([](system_error) { std::cout << "task done\n"; });
}
int main() {
task_foo();
std::cout << "Before doing work\n";
svc.run(); // blocks!
std::cout << "After doing work\n";
}
版画
Before doing work
task done
After doing work
您始终可以使用期货,然后等待冻结:
#include <boost/asio.hpp>
#include <boost/asio/high_resolution_timer.hpp>
#include <boost/make_shared.hpp>
#include <future>
#include <iostream>
#include <thread>
using namespace std::chrono_literals;
using namespace boost::asio;
using boost::system::system_error;
io_service svc;
high_resolution_timer deadline(svc, 3s);
std::future<int> task_foo() {
auto p = boost::make_shared<std::promise<int> >();
auto fut = p->get_future();
deadline.async_wait([p](system_error) {
std::cout << "task done\n";
p->set_value(42);
});
return fut;
}
int main() {
auto foo = task_foo();
std::cout << "Before doing work\n";
std::thread([] { svc.run(); }).detach(); // doesn't block!
std::cout << "After starting work\n"; // happens before task completion
auto result = foo.get(); // blocks again!
std::cout << "Task result: " << result << "\n";
}
版画
Before doing work
After starting work
task done
Task result: 42
这样,即使特定任务同步完成,您仍然可以使io_service同时运行,并且不需要完成它( foo.get()
)
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