[asio-users] Does handler_type need to be used in std::function?

[peter j. <p.j...@gm...>]

Hello,

I've been using Asio for a long time and few months ago I went about to try
it with coroutines. I'm quite amazed at how great they work together, but
here is something I'm not understanding with respect to converting the
yield context into a handler. I.e. it seems to be that one has to follow
this exact path:

1. create handler_type by passing yield_context to it
2. create async_result by passing the above handler_type to it
3. create an (e.g. ) std::function handler by passing the above
handler_type to it

Now, it's obvious that creating handler_type has to be the first step
(because it's used as an argument to the other two). But if I switch the
steps #2 and #3, I'll see a crash.

Here is an example where one can see it:

https://gist.github.com/inetic/dc9081baf45ec4b60037#file-async_result-cpp-L29

Equally puzzling is that if I don't do the step #3, but instead just
attempt to execute
the instance of handler_type created in step #1, I get a crash as well.

This crash can be seen in this example:

https://gist.github.com/redlizard/cd537ec8f5e278e97293041a73572793#file-cpp

And here how simply doing the step #3 and executing the std::function
instead of the handler_type fixes it:

https://gist.github.com/redlizard/cd537ec8f5e278e97293041a73572793#gistcomment-2272277

Is this a documented behavior, is it a bug, or is it something that is
normally obvious to anyone understanding how Boost.Coroutine works?

I'm currently using boost version 1.58 (as it's the default with current
Ubuntu).

Cheers,

Peter