Re: [Boost-users] What is the effective way to use boost::asio::deadline_timer for udp socket receive_from?

Subject: Re: [Boost-users] What is the effective way to use boost::asio::deadline_timer for udp socket receive_from?
From: TONGARI J (tongari95_at_[hidden])
Date: 2017-04-12 15:46:53

2017-04-12 19:17 GMT+08:00 jupiter via Boost-users <
boost-users_at_[hidden]>:

> Hi,
>
> My program needs a sync udp socket send / receiver so I use the
> deadline_timer as timeout for udp socket receive_from on Debian Jessie:
>
> boost::asio::deadline_timer deadline(io_service,
> boost::posix_time::seconds(2));
>
> In checkDeadline function, when the timer expires, it calls socket.cancel,
> otherwise calls the deadline.async_wait(checkDeadline); again.
>
> Apparently when the program runs to socket.receive_from(), it is blocked
> and the timer is never called because both socket.receive_from and the
> timer in the same thread.
>
> I've been thinking to run the timer in another thread, but I checked
> Internet, there are comments said deadline_timer is not thread safe, please
> correct me if I am wrong here. It will be a simple solution for me if I can
> run timer on another thread. Anyone has other ideas to run the timer
> effectively?
>

Unfortunately, asio timers are useless with those blocking calls, you have
to use the async version (e.g. async_receive_from) and code in async
fashion instead.