Caleb Epstein wrote:

On 3/4/06, Jeff Flinn <TriumphSprint2000@hotmail.com> wrote:

I'm moving an MFC net app to asio. In that app CAsyncSocket/CSocket are

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created using port=0, which MFC docs states: 'Windows Sockets to select a port'. Is there a similar facility in asio? If not any suggestions on a portable technique to get an available port?

The default constructor for ipv4::tcp::endpoint initializes the port to 0. Just pass a default-constructed endpoint to your socket_acceptor's ctor or to its bind method.

You can then use the get_local_endpoint method to get the value of the port that was allocated by the OS.

Thanks again Caleb. Jeff Flinn

On Mar 6, 2006, at 15:29, Jeff Flinn wrote:

Caleb Epstein wrote:

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On 3/4/06, Jeff Flinn <TriumphSprint2000@hotmail.com> wrote:

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You can then use the get_local_endpoint method to get the value of the port that was allocated by the OS.

This brings up one of the bothersome aspects of asio interface, IMHO. Functions like:

template<typename Endpoint> void get_local_endpoint (Endpoint &endpoint)

make it difficult to use in the context of an initializer list.

typedef boost::asio::ipv4::tcp::endpoint tEndpoint;

some_class( ... ) : mSocketPtr( ... ) ... , mPort( mSocketPtr->get_local_endpoint().port() ) {}

On the asio cvs there's a new member function, local_endpoint(), which returns the endpoint.

obviously fails to compile. Rather than

, mPort( mSocketPtr->local_endpoint_ref<tEndpoint>().port() )

Any reason this was not considered? The same goes for host and host resolver's get_host_by_name.

-- Arvid Norberg

Hi Jeff, --- Jeff Flinn <TriumphSprint2000@hotmail.com> wrote:

This brings up one of the bothersome aspects of asio interface, IMHO.

Functions like:

template<typename Endpoint> void get_local_endpoint (Endpoint &endpoint)

make it difficult to use in the context of an initializer list.

As Arvid mentioned, this has already changed in asio's cvs repository. It's part of a change suggested during the review to add stronger typing for the socket classes. For example, you can now write: ip::tcp::socket socket(io_service); ... ip::tcp::endpoint ep = socket.local_endpoint();

Any reason this was not considered? The same goes for host and host resolver's get_host_by_name.

I intend to replace the host_resolver class with a new interface based on getaddrinfo/getnameinfo that can support both IPv4 and IPv6. This will probably return an iterator that can be used to enumerate all endpoints that match some criteria. E.g. something like: ip::tcp::resolver resolver(io_service); ip::tcp::resolver::query query("some.host", "daytime"); ip::tcp::resolver::iterator iter = resolver.resolve(query); ip::tcp::resolver::iterator end; while (iter != end) { ip::tcp::endpoint endpoint = iter->endpoint(); ... ++iter; } Cheers, Chris