GSocketListener

GSocketListener — Helper for accepting network client connections

Properties

gint listen-backlog Read / Write / Construct

Signals

Types and Values

Object Hierarchy

    GObject
    ╰── GSocketListener
        ╰── GSocketService

Includes

#include <gio/gio.h>

Description

A GSocketListener is an object that keeps track of a set of server sockets and helps you accept sockets from any of the socket, either sync or async.

If you want to implement a network server, also look at GSocketService and GThreadedSocketService which are subclass of GSocketListener that makes this even easier.

Functions

g_socket_listener_new ()

GSocketListener *
g_socket_listener_new (void);

Creates a new GSocketListener with no sockets to listen for. New listeners can be added with e.g. g_socket_listener_add_address() or g_socket_listener_add_inet_port().

Returns

a new GSocketListener.

Since: 2.22


g_socket_listener_add_socket ()

gboolean
g_socket_listener_add_socket (GSocketListener *listener,
                              GSocket *socket,
                              GObject *source_object,
                              GError **error);

Adds socket to the set of sockets that we try to accept new clients from. The socket must be bound to a local address and listened to.

source_object will be passed out in the various calls to accept to identify this particular source, which is useful if you're listening on multiple addresses and do different things depending on what address is connected to.

The socket will not be automatically closed when the listener is finalized unless the listener held the final reference to the socket. Before GLib 2.42, the socket was automatically closed on finalization of the listener , even if references to it were held elsewhere.

Parameters

listener

a GSocketListener

 

socket

a listening GSocket

 

source_object

Optional GObject identifying this source.

[allow-none]

error

GError for error reporting, or NULL to ignore.

 

Returns

TRUE on success, FALSE on error.

Since: 2.22


g_socket_listener_add_address ()

gboolean
g_socket_listener_add_address (GSocketListener *listener,
                               GSocketAddress *address,
                               GSocketType type,
                               GSocketProtocol protocol,
                               GObject *source_object,
                               GSocketAddress **effective_address,
                               GError **error);

Creates a socket of type type and protocol protocol , binds it to address and adds it to the set of sockets we're accepting sockets from.

Note that adding an IPv6 address, depending on the platform, may or may not result in a listener that also accepts IPv4 connections. For more deterministic behavior, see g_socket_listener_add_inet_port().

source_object will be passed out in the various calls to accept to identify this particular source, which is useful if you're listening on multiple addresses and do different things depending on what address is connected to.

If successful and effective_address is non-NULL then it will be set to the address that the binding actually occurred at. This is helpful for determining the port number that was used for when requesting a binding to port 0 (ie: "any port"). This address, if requested, belongs to the caller and must be freed.

Parameters

listener

a GSocketListener

 

address

a GSocketAddress

 

type

a GSocketType

 

protocol

a GSocketProtocol

 

source_object

Optional GObject identifying this source.

[allow-none]

effective_address

location to store the address that was bound to, or NULL.

[out][allow-none]

error

GError for error reporting, or NULL to ignore.

 

Returns

TRUE on success, FALSE on error.

Since: 2.22


g_socket_listener_add_inet_port ()

gboolean
g_socket_listener_add_inet_port (GSocketListener *listener,
                                 guint16 port,
                                 GObject *source_object,
                                 GError **error);

Helper function for g_socket_listener_add_address() that creates a TCP/IP socket listening on IPv4 and IPv6 (if supported) on the specified port on all interfaces.

source_object will be passed out in the various calls to accept to identify this particular source, which is useful if you're listening on multiple addresses and do different things depending on what address is connected to.

Parameters

listener

a GSocketListener

 

port

an IP port number (non-zero)

 

source_object

Optional GObject identifying this source.

[allow-none]

error

GError for error reporting, or NULL to ignore.

 

Returns

TRUE on success, FALSE on error.

Since: 2.22


g_socket_listener_add_any_inet_port ()

guint16
g_socket_listener_add_any_inet_port (GSocketListener *listener,
                                     GObject *source_object,
                                     GError **error);

Listens for TCP connections on any available port number for both IPv6 and IPv4 (if each is available).

This is useful if you need to have a socket for incoming connections but don't care about the specific port number.

source_object will be passed out in the various calls to accept to identify this particular source, which is useful if you're listening on multiple addresses and do different things depending on what address is connected to.

Parameters

listener

a GSocketListener

 

source_object

Optional GObject identifying this source.

[allow-none]

error

a GError location to store the error occurring, or NULL to ignore.

 

Returns

the port number, or 0 in case of failure.

Since: 2.24


g_socket_listener_accept ()

GSocketConnection *
g_socket_listener_accept (GSocketListener *listener,
                          GObject **source_object,
                          GCancellable *cancellable,
                          GError **error);

Blocks waiting for a client to connect to any of the sockets added to the listener. Returns a GSocketConnection for the socket that was accepted.

If source_object is not NULL it will be filled out with the source object specified when the corresponding socket or address was added to the listener.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be returned.

Parameters

listener

a GSocketListener

 

source_object

location where GObject pointer will be stored, or NULL.

[out][transfer none][allow-none]

cancellable

optional GCancellable object, NULL to ignore.

[allow-none]

error

GError for error reporting, or NULL to ignore.

 

Returns

a GSocketConnection on success, NULL on error.

[transfer full]

Since: 2.22


g_socket_listener_accept_async ()

void
g_socket_listener_accept_async (GSocketListener *listener,
                                GCancellable *cancellable,
                                GAsyncReadyCallback callback,
                                gpointer user_data);

This is the asynchronous version of g_socket_listener_accept().

When the operation is finished callback will be called. You can then call g_socket_listener_accept_socket() to get the result of the operation.

Parameters

listener

a GSocketListener

 

cancellable

a GCancellable, or NULL.

[allow-none]

callback

a GAsyncReadyCallback.

[scope async]

user_data

user data for the callback.

[closure]

Since: 2.22


g_socket_listener_accept_finish ()

GSocketConnection *
g_socket_listener_accept_finish (GSocketListener *listener,
                                 GAsyncResult *result,
                                 GObject **source_object,
                                 GError **error);

Finishes an async accept operation. See g_socket_listener_accept_async()

Parameters

listener

a GSocketListener

 

result

a GAsyncResult.

 

source_object

Optional GObject identifying this source.

[out][transfer none][allow-none]

error

a GError location to store the error occurring, or NULL to ignore.

 

Returns

a GSocketConnection on success, NULL on error.

[transfer full]

Since: 2.22


g_socket_listener_accept_socket ()

GSocket *
g_socket_listener_accept_socket (GSocketListener *listener,
                                 GObject **source_object,
                                 GCancellable *cancellable,
                                 GError **error);

Blocks waiting for a client to connect to any of the sockets added to the listener. Returns the GSocket that was accepted.

If you want to accept the high-level GSocketConnection, not a GSocket, which is often the case, then you should use g_socket_listener_accept() instead.

If source_object is not NULL it will be filled out with the source object specified when the corresponding socket or address was added to the listener.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be returned.

Parameters

listener

a GSocketListener

 

source_object

location where GObject pointer will be stored, or NULL.

[out][transfer none][allow-none]

cancellable

optional GCancellable object, NULL to ignore.

[allow-none]

error

GError for error reporting, or NULL to ignore.

 

Returns

a GSocket on success, NULL on error.

[transfer full]

Since: 2.22


g_socket_listener_accept_socket_async ()

void
g_socket_listener_accept_socket_async (GSocketListener *listener,
                                       GCancellable *cancellable,
                                       GAsyncReadyCallback callback,
                                       gpointer user_data);

This is the asynchronous version of g_socket_listener_accept_socket().

When the operation is finished callback will be called. You can then call g_socket_listener_accept_socket_finish() to get the result of the operation.

Parameters

listener

a GSocketListener

 

cancellable

a GCancellable, or NULL.

[allow-none]

callback

a GAsyncReadyCallback.

[scope async]

user_data

user data for the callback.

[closure]

Since: 2.22


g_socket_listener_accept_socket_finish ()

GSocket *
g_socket_listener_accept_socket_finish
                               (GSocketListener *listener,
                                GAsyncResult *result,
                                GObject **source_object,
                                GError **error);

Finishes an async accept operation. See g_socket_listener_accept_socket_async()

Parameters

listener

a GSocketListener

 

result

a GAsyncResult.

 

source_object

Optional GObject identifying this source.

[out][transfer none][allow-none]

error

a GError location to store the error occurring, or NULL to ignore.

 

Returns

a GSocket on success, NULL on error.

[transfer full]

Since: 2.22


g_socket_listener_close ()

void
g_socket_listener_close (GSocketListener *listener);

Closes all the sockets in the listener.

Parameters

listener

a GSocketListener

 

Since: 2.22


g_socket_listener_set_backlog ()

void
g_socket_listener_set_backlog (GSocketListener *listener,
                               int listen_backlog);

Sets the listen backlog on the sockets in the listener.

See g_socket_set_listen_backlog() for details

Parameters

listener

a GSocketListener

 

listen_backlog

an integer

 

Since: 2.22

Types and Values

GSocketListener

typedef struct _GSocketListener GSocketListener;

A helper class for network servers to listen for and accept connections.

Since: 2.22


enum GSocketListenerEvent

Describes an event occurring on a GSocketListener. See the “event” signal for more details.

Additional values may be added to this type in the future.

Members

G_SOCKET_LISTENER_BINDING

The listener is about to bind a socket.

 

G_SOCKET_LISTENER_BOUND

The listener has bound a socket.

 

G_SOCKET_LISTENER_LISTENING

The listener is about to start listening on this socket.

 

G_SOCKET_LISTENER_LISTENED

The listener is now listening on this socket.

 

Since: 2.46

Property Details

The “listen-backlog” property

  “listen-backlog”           gint

outstanding connections in the listen queue.

Flags: Read / Write / Construct

Allowed values: [0,2000]

Default value: 10

Signal Details

The “event” signal

void
user_function (GSocketListener     *listener,
               GSocketListenerEvent event,
               GSocket             *socket,
               gpointer             user_data)

Emitted when listener 's activity on socket changes state. Note that when listener is used to listen on both IPv4 and IPv6, a separate set of signals will be emitted for each, and the order they happen in is undefined.

Parameters

listener

the GSocketListener

 

event

the event that is occurring

 

socket

the GSocket the event is occurring on

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last

Since: 2.46