Re: [Cppcms-users] Can I create an asynchronous socket connection from within an asynchronously mounted application?

[Dietrich M. <die...@gm...>]

Actually the problem was that I used multiple sockets in a vector. So I
eventually iterated over them and the buffer might have been copied around.
The socket could not be copied as it had to be stored as a shared_ptr.
Finally I solved the issue by moving the sockets to a vector of unique_ptr
and the problem was gone.
Thanks for you help anyway!

On Thu, Oct 18, 2012 at 1:53 PM, Artyom Beilis <art...@ya...> wrote:

>
> > From: Dietrich Müller <die...@gm...>
> >To: cpp...@li...
> >Sent: Friday, October 12, 2012 6:32 PM
> >Subject: [Cppcms-users] Can I create an asynchronous socket connection
> from within an asynchronously mounted application?
> >
> >
> >Hello, I try to create a socket connection from within my application and
> I seem to fail.
> >I tried to setup the code like in this boost asio sample for an
> asynchronous http client (
> http://www.boost.org/doc/libs/1_51_0/doc/html/boost_asio/example/http/client/async_client.cpp)
> without the resolving part.
> >Btw this resolver is pretty useful. Can it be integrated into booster aio?
> >
> >//the  call
> >socket->async_connect(endpoint, std::bind(&ClassX::onConnected, this,
> std::placeholders::_1));
> >
> >//the first callback
> >void ClassX::onConnected(const booster::system::error_code &e) {
> >  if(!e)
> >    //print some member of ClassX
> >    //...
> >    //and write something to the socket
> >    socket->async_write(buff, std::bind(&ClassX::onWritten, this,
> std::placeholders::_1));
> >}
> >
>
> Where buf's content resides? The memory areas pointed by buff should
> remain valid untill asynchronous write
> operation is cimpleted.
>
> Also if you want any help, show the full code
>
>
>
> >//onWritten callback
>
> >//onRead callback
> >
> >Now the problem is that as soon as I access a class member in any
> callback, the result is a segmentation fault.
> >If I pass shared_from_this() and not this I get a assertion error in
> enable_shared_from_this.h:56 that p.get() == this is not true.
>
>
> What is shared from this? I assume you try to make application with
> shared_from_this? You can't. Because
> it is not created with shared_ptr, also if application exists all the time
> than you don't need to care
> about shared from this stuff and use ordinary this.
>
> >I think the problems are related to some synchronisation issues between
> the main and the application thread, as the synchronous calls work.
> >Please give me some advice how I correctly use the socket in my
> application.
>
>
>
> If you use asynchronous application than its thread and the event loop
> threads are the same.
>
>
> **Next Time**
>
> Show the full code.
> Artyom Beilis
> --------------
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