GSocketConnectable: GIO Reference Manual

GSocketConnectable

GSocketConnectable — Interface for potential socket endpoints

Functions

GSocketAddressEnumerator *	g_socket_connectable_enumerate ()
GSocketAddressEnumerator *	g_socket_connectable_proxy_enumerate ()
GSocketAddress *	g_socket_address_enumerator_next ()
void	g_socket_address_enumerator_next_async ()
GSocketAddress *	g_socket_address_enumerator_next_finish ()

Properties

GSocketConnectable *	connectable	Read / Write / Construct Only
guint	default-port	Read / Write / Construct Only
GProxyResolver *	proxy-resolver	Read / Write / Construct
gchar *	uri	Read / Write / Construct Only

Types and Values

	GSocketConnectable
struct	GSocketConnectableIface
	GSocketAddressEnumerator
	GProxyAddressEnumerator

Object Hierarchy

    GInterface
    ╰── GSocketConnectable
    GObject
    ├── GSocketAddressEnumerator
    │   ╰── GProxyAddressEnumerator
    ╰── GSocketAddressEnumerator
        ╰── GProxyAddressEnumerator

Prerequisites

GSocketConnectable requires GObject.

Known Implementations

GSocketConnectable is implemented by GInetSocketAddress, GNetworkAddress, GNetworkService, GProxyAddress, GSocketAddress and GUnixSocketAddress.

Includes

#include <gio/gio.h>

Description

Objects that describe one or more potential socket endpoints implement GSocketConnectable. Callers can then use g_socket_connectable_enumerate() to get a GSocketAddressEnumerator to try out each socket address in turn until one succeeds, as shown in the sample code below.

MyConnectionType *
connect_to_host (const char    *hostname,
                 guint16        port,
                 GCancellable  *cancellable,
                 GError       **error)
{
  MyConnection *conn = NULL;
  GSocketConnectable *addr;
  GSocketAddressEnumerator *enumerator;
  GSocketAddress *sockaddr;
  GError *conn_error = NULL;

  addr = g_network_address_new (hostname, port);
  enumerator = g_socket_connectable_enumerate (addr);
  g_object_unref (addr);

  // Try each sockaddr until we succeed. Record the first connection error,
  // but not any further ones (since they'll probably be basically the same
  // as the first).
  while (!conn && (sockaddr = g_socket_address_enumerator_next (enumerator, cancellable, error))
    {
      conn = connect_to_sockaddr (sockaddr, conn_error ? NULL : &conn_error);
      g_object_unref (sockaddr);
    }
  g_object_unref (enumerator);

  if (conn)
    {
      if (conn_error)
        {
          // We couldn't connect to the first address, but we succeeded
          // in connecting to a later address.
          g_error_free (conn_error);
        }
      return conn;
    }
  else if (error)
    {
      /// Either initial lookup failed, or else the caller cancelled us.
      if (conn_error)
        g_error_free (conn_error);
      return NULL;
    }
  else
    {
      g_error_propagate (error, conn_error);
      return NULL;
    }
}

Functions

g_socket_connectable_enumerate ()

GSocketAddressEnumerator *
g_socket_connectable_enumerate (GSocketConnectable *connectable);

Creates a GSocketAddressEnumerator for connectable .

Parameters

connectable

a GSocketConnectable

Returns

a new GSocketAddressEnumerator.

[transfer full]

Since 2.22

g_socket_connectable_proxy_enumerate ()

GSocketAddressEnumerator *
g_socket_connectable_proxy_enumerate (GSocketConnectable *connectable);

Creates a GSocketAddressEnumerator for connectable that will return GProxyAddresses for addresses that you must connect to via a proxy.

If connectable does not implement g_socket_connectable_proxy_enumerate(), this will fall back to calling g_socket_connectable_enumerate().

Parameters

connectable

a GSocketConnectable

Returns

a new GSocketAddressEnumerator.

[transfer full]

Since 2.26

g_socket_address_enumerator_next ()

GSocketAddress *
g_socket_address_enumerator_next (GSocketAddressEnumerator *enumerator,
                                  GCancellable *cancellable,
                                  GError **error);

Retrieves the next GSocketAddress from enumerator . Note that this may block for some amount of time. (Eg, a GNetworkAddress may need to do a DNS lookup before it can return an address.) Use g_socket_address_enumerator_next_async() if you need to avoid blocking.

If enumerator is expected to yield addresses, but for some reason is unable to (eg, because of a DNS error), then the first call to g_socket_address_enumerator_next() will return an appropriate error in *error . However, if the first call to g_socket_address_enumerator_next() succeeds, then any further internal errors (other than cancellable being triggered) will be ignored.

Parameters

enumerator	a GSocketAddressEnumerator
cancellable	optional GCancellable object, `NULL` to ignore.	[allow-none]
error	a GError.

Returns

a GSocketAddress (owned by the caller), or NULL on error (in which case *error will be set) or if there are no more addresses.

[transfer full]

g_socket_address_enumerator_next_async ()

void
g_socket_address_enumerator_next_async
                               (GSocketAddressEnumerator *enumerator,
                                GCancellable *cancellable,
                                GAsyncReadyCallback callback,
                                gpointer user_data);

Asynchronously retrieves the next GSocketAddress from enumerator and then calls callback , which must call g_socket_address_enumerator_next_finish() to get the result.

Parameters

enumerator	a GSocketAddressEnumerator
cancellable	optional GCancellable object, `NULL` to ignore.	[allow-none]
callback	a GAsyncReadyCallback to call when the request is satisfied.	[scope async]
user_data	the data to pass to callback function.	[closure]

g_socket_address_enumerator_next_finish ()

GSocketAddress *
g_socket_address_enumerator_next_finish
                               (GSocketAddressEnumerator *enumerator,
                                GAsyncResult *result,
                                GError **error);

Retrieves the result of a completed call to g_socket_address_enumerator_next_async(). See g_socket_address_enumerator_next() for more information about error handling.

Parameters

enumerator	a GSocketAddressEnumerator
result	a GAsyncResult
error	a GError

Returns

a GSocketAddress (owned by the caller), or NULL on error (in which case *error will be set) or if there are no more addresses.

[transfer full]

Types and Values