Re: [Boost-users] boost::asio blocking socket read with timeout with multiple threads

Subject: Re: [Boost-users] boost::asio blocking socket read with timeout with multiple threads
From: tom_at_[hidden]
Date: 2018-03-23 10:23:59

> Of course the correct way to "cancel" a sync call in linux is to raise a
> signal, which should cause the socket's read to return with EINTR.

Hmm. Can't see any evidence of it working in my test. I've made my deadline callback do a raise(SIGALRM). If I don't have a handler for that signal, then my process terminates, which I guess is fair enough. If I have a (boost asio) handler and essentially ignore the signal (just print "signal handled" from my signal handler), the signal is handled, but my read doesn't return. My recollection of the boost asio code for socket recv is that it doesn't simply perform a raw socket recv call, but rather it loops in case of error, with a "poll" call in there too.

So while that technique may work OK for a raw socket, it doesn't work with asio.