Re: [Boost-users] Boost::Asio crashes all the time when starting multiple connections

Subject: Re: [Boost-users] Boost::Asio crashes all the time when starting multiple connections
From: Igor R (boost.lists_at_[hidden])
Date: 2011-06-14 06:28:02

> It seems to work fine for one or two connections, but if more connections
> are openend, boost suddenly crashes, mostly in the bind-template.hpp:

To be more exact, you application crashes ;).

> Â  Â template<class A1, class A2> result_type operator()(A1 const & a1, A2
> const & a2)
> Â  Â {
> Â  Â  Â  Â list2<A1 const &, A2 const &> a(a1, a2);
> CRASH ===> Â  Â  Â  Â  BOOST_BIND_RETURN l_(type<result_type>(), f_, a, 0);
> Â  Â }

This is an invocation of some binder. In your case it's an invocation
of a completion handler.
It crashes because it's bound to a dead (i.e. deleted) object - which
is apparently reasonable, since you don't use shared_from_this()
idiom.
Specifically in your code the problem is the following:
1) You issue 2 async.requests:
   socket_.async_read_some(..., boost::bind(&session::handle_read, this,...));
   sqlsocket_.async_read_some(...,
boost::bind(&session::handle_sqlserver_read, this, ...));
2) One of the requests ends with an error (even just EOF), and you
delete the connection object.
3) Now the completion handler of the seconds request is being invoked... crash.

Conclusion: do not bind your handlers to "this", do not delete objects
manually. Instead, use shared_from_this() idiom.