[62:7] extends: object
A GSocket is a low-level networking primitive. It is a more or less direct
mapping of the BSD socket API in a portable GObject based API. It supports
both the UNIX socket implementations and winsock2 on Windows. GSocket is
the platform independent base upon which the higher level network primitives
are based. Applications are not typically meant to use it directly, but
rather through classes like [class@Gio.SocketClient],
[class@Gio.SocketService] and [class@Gio.SocketConnection]. However there may
be cases where direct use of GSocket is useful. GSocket implements the
[iface@Gio.Initable] interface, so if it is manually constructed by e.g.
[ctor@GObject.Object.new] you must call [method@Gio.Initable.init] and check
the results before using the object. This is done automatically in
[ctor@Gio.Socket.new] and [ctor@Gio.Socket.new_from_fd], so these functions
can return NULL. Sockets operate in two general modes, blocking or
non-blocking. When in blocking mode all operations (which don’t take an
explicit blocking parameter) block until the requested operation is finished
or there is an error. In non-blocking mode all calls that would block return
immediately with a G_IO_ERROR_WOULD_BLOCK error. To know when a call would
successfully run you can call [method@Gio.Socket.condition_check], or
[method@Gio.Socket.condition_wait]. You can also use
[method@Gio.Socket.create_source] and attach it to a [type@GLib.MainContext]
to get callbacks when I/O is possible. Note that all sockets are always set
to non blocking mode in the system, and blocking mode is emulated in
GSocket. When working in non-blocking mode applications should always be
able to handle getting a G_IO_ERROR_WOULD_BLOCK error even when some other
function said that I/O was possible. This can easily happen in case of a race
condition in the application, but it can also happen for other reasons. For
instance, on Windows a socket is always seen as writable until a write
returns G_IO_ERROR_WOULD_BLOCK. GSockets can be either connection
oriented or datagram based. For connection oriented types you must first
establish a connection by either connecting to an address or accepting a
connection from another address. For connectionless socket types the
target/source address is specified or received in each I/O operation. All
socket file descriptors are set to be close-on-exec. Note that creating a
GSocket causes the signal SIGPIPE to be ignored for the remainder of the
program. If you are writing a command-line utility that uses GSocket, you
may need to take into account the fact that your program will not
automatically be killed if it tries to write to stdout after it has been
closed. Like most other APIs in GLib, GSocket is not inherently thread
safe. To use a GSocket concurrently from multiple threads, you must
implement your own locking. ## Nagle’s algorithm Since GLib 2.80, GSocket
will automatically set the TCP_NODELAY option on all G_SOCKET_TYPE_STREAM
sockets. This disables Nagle’s
algorithm as it typically
does more harm than good on modern networks. If your application needs
Nagle’s algorithm enabled, call [method@Gio.Socket.set_option] after
constructing a GSocket to enable it: ```c socket = g_socket_new (…,
G_SOCKET_TYPE_STREAM, …); if (socket != NULL) { g_socket_set_option (socket,
IPPROTO_TCP, TCP_NODELAY, FALSE, &local_error); // handle error if needed }
#### Members
- **handleObj**
- **lib**
- **retainedCallbacks**
- **signalHandlerNames**
- **signalSetterHandlers**
#### Methods
- **GSocket** (`family = null, type = null, protocol = null`)
> Creates a new #GSocket with the defined family, type and protocol. If
- **@protocol** `is` 0 (%G_SOCKET_PROTOCOL_DEFAULT) the default protocol type for the family and type is used. The @protocol is a family and type specific int that specifies what kind of protocol to use. #GSocketProtocol lists several common ones. Many families only support one protocol, and use 0 for this, others support several and using 0 means to use the default protocol for the family and type. The protocol id is passed directly to the operating system, so you can use protocols not listed in #GSocketProtocol if you know the protocol number used for it.
- **@p** `family` is the socket family to use, e.g. %G_SOCKET_FAMILY_IPV4..
- **@p** `type` is the socket type to use..
- **@p** `protocol` is the id of the protocol to use, or 0 for default..
- **toNativeHandle** (`Source`)
> Normalizes a constructor argument into a raw pointer carrier. Accepts a raw NativeHandle, a raw NativeBuffer returned from `fn.call(...)`, another generated wrapper exposing `handle()`, or null. Returns null when the argument carries no pointer.
- **@p** `Source` is the raw handle, raw buffer, wrapper, or null.
- **@r** `A` raw pointer carrier or null when no pointer is present.
- **getLib** ()
> Returns the opened native library for this generated wrapper.
- **@r** `The` opened native library.
- **handle** ()
> Returns the wrapped NativeHandle.
- **@r** `The` wrapped NativeHandle.
- **isNull** ()
> Returns true when the wrapped handle is null.
- **@r** `A` bool.
- **describe** ()
> Returns a small string for debugging generated wrappers.
- **@r** `A` string.
- **asObject** ()
> Wraps this handle as `GObject`.
- **@r** `A` `GObject` object.
- **asDatagramBased** ()
> Wraps this handle as `GDatagramBased`.
- **@r** `A` `GDatagramBased` object.
- **asInitable** ()
> Wraps this handle as `GInitable`.
- **@r** `A` `GInitable` object.
- **getProperty** (`string Name`)
> Reads one generated property by name.
- **setProperty** (`string Name, Value`)
> Writes one generated property by name.
- **setBlocking** (`bool Value`)
> Whether I/O on this socket is blocking.
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setBroadcast** (`bool Value`)
> Whether the socket should allow sending to broadcast addresses.
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setKeepalive** (`bool Value`)
> Whether to keep the connection alive by sending periodic pings.
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setListenbacklog** (`int Value`)
> The number of outstanding connections in the listen queue.
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setMulticastloopback** (`bool Value`)
> Whether outgoing multicast packets loop back to the local host.
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setMulticastttl** (`int Value`)
> Time-to-live out outgoing multicast packets
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setTimeout** (`int Value`)
> The timeout in seconds on socket I/O
- **@p** `Value` is the new property value.
- **@r** `None.`
- **setTtl** (`int Value`)
> Time-to-live for outgoing unicast packets
- **@p** `Value` is the new property value.
- **@r** `None.`
- **accept** (`object cancellable`)
> Accept incoming connections on a connection-based socket. This removes the first outstanding connection request from the listening socket and creates a #GSocket object for it. The @socket must be bound to a local address with g_socket_bind() and must be listening for incoming connections (g_socket_listen()). If there are no outstanding connections then the operation will block or return %G_IO_ERROR_WOULD_BLOCK if non-blocking I/O is enabled. To be notified of an incoming connection, wait for the %G_IO_IN condition.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `a` new #GSocket, or %NULL on error. Free the returned object with g_object_unref()..
- **bind** (`object address, bool allow_reuse`)
> When a socket is created it is attached to an address family, but it doesn't have an address in this family. g_socket_bind() assigns the address (sometimes called name) of the socket. It is generally required to bind to a local address before you can receive connections. (See g_socket_listen() and g_socket_accept() ). In certain situations, you may also want to bind a socket that will be used to initiate connections, though this is not normally required. If @socket is a TCP socket, then
- **@allow_reuse** `controls` the setting of the `SO_REUSEADDR` socket option; normally it should be %TRUE for server sockets (sockets that you will eventually call g_socket_accept() on), and %FALSE for client sockets. (Failing to set this flag on a server socket may cause g_socket_bind() to return %G_IO_ERROR_ADDRESS_IN_USE if the server program is stopped and then immediately restarted.) If @socket is a UDP socket, then
- **@allow_reuse** `determines` whether or not other UDP sockets can be bound to the same address at the same time. In particular, you can have several UDP sockets bound to the same address, and they will all receive all of the multicast and broadcast packets sent to that address. (The behavior of unicast UDP packets to an address with multiple listeners is not defined.)
- **@p** `address` is a #GSocketAddress specifying the local address..
- **@p** `allow_reuse` is whether to allow reusing this address.
- **@r** `%TRUE` on success, %FALSE on error..
- **check\_connect\_result** ()
> Checks and resets the pending connect error for the socket. This is used to check for errors when g_socket_connect() is used in non-blocking mode.
- **@r** `%TRUE` if no error, %FALSE otherwise, setting @error to the error.
- **close** ()
> Closes the socket, shutting down any active connection. Closing a socket does not wait for all outstanding I/O operations to finish, so the caller should not rely on them to be guaranteed to complete even if the close returns with no error. Once the socket is closed, all other operations will return %G_IO_ERROR_CLOSED. Closing a socket multiple times will not return an error. Sockets will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible. Beware that due to the way that TCP works, it is possible for recently-sent data to be lost if either you close a socket while the %G_IO_IN condition is set, or else if the remote connection tries to send something to you after you close the socket but before it has finished reading all of the data you sent. There is no easy generic way to avoid this problem; the easiest fix is to design the network protocol such that the client will never send data "out of turn". Another solution is for the server to half-close the connection by calling g_socket_shutdown() with only the @shutdown_write flag set, and then wait for the client to notice this and close its side of the connection, after which the server can safely call g_socket_close(). (This is what #GTcpConnection does if you call g_tcp_connection_set_graceful_disconnect(). But of course, this only works if the client will close its connection after the server does.)
- **@r** `%TRUE` on success, %FALSE on error.
- **condition\_check** (`string condition`)
> Checks on the readiness of @socket to perform operations. The operations specified in @condition are checked for and masked against the currently-satisfied conditions on @socket. The result is returned. Note that on Windows, it is possible for an operation to return %G_IO_ERROR_WOULD_BLOCK even immediately after g_socket_condition_check() has claimed that the socket is ready for writing. Rather than calling g_socket_condition_check() and then writing to the socket if it succeeds, it is generally better to simply try writing to the socket right away, and try again later if the initial attempt returns %G_IO_ERROR_WOULD_BLOCK. It is meaningless to specify %G_IO_ERR or %G_IO_HUP in condition; these conditions will always be set in the output if they are true. This call never blocks.
- **@p** `condition` is a #GIOCondition mask to check.
- **@r** `the` @GIOCondition mask of the current state.
- **condition\_timed\_wait** (`string condition, int timeout_us, object cancellable`)
> Waits for up to @timeout_us microseconds for @condition to become true on
- **@socket.** `If` the condition is met, %TRUE is returned. If @cancellable is cancelled before the condition is met, or if @timeout_us (or the socket's #GSocket:timeout) is reached before the condition is met, then %FALSE is returned and @error, if non-%NULL, is set to the appropriate value (%G_IO_ERROR_CANCELLED or %G_IO_ERROR_TIMED_OUT). If you don't want a timeout, use g_socket_condition_wait(). (Alternatively, you can pass -1 for @timeout_us.) Note that although @timeout_us is in microseconds for consistency with other GLib APIs, this function actually only has millisecond resolution, and the behavior is undefined if @timeout_us is not an exact number of milliseconds.
- **@p** `condition` is a #GIOCondition mask to wait for.
- **@p** `timeout_us` is the maximum time (in microseconds) to wait, or -1.
- **@p** `cancellable` is a #GCancellable, or %NULL.
- **@r** `%TRUE` if the condition was met, %FALSE otherwise.
- **condition\_wait** (`string condition, object cancellable`)
> Waits for @condition to become true on @socket. When the condition is met, %TRUE is returned. If @cancellable is cancelled before the condition is met, or if the socket has a timeout set and it is reached before the condition is met, then %FALSE is returned and @error, if non-%NULL, is set to the appropriate value (%G_IO_ERROR_CANCELLED or %G_IO_ERROR_TIMED_OUT). See also g_socket_condition_timed_wait().
- **@p** `condition` is a #GIOCondition mask to wait for.
- **@p** `cancellable` is a #GCancellable, or %NULL.
- **@r** `%TRUE` if the condition was met, %FALSE otherwise.
- **connect** (`object address, object cancellable`)
> Connect the socket to the specified remote address. For connection oriented socket this generally means we attempt to make a connection to the @address. For a connection-less socket it sets the default address for g_socket_send() and discards all incoming datagrams from other sources. Generally connection oriented sockets can only connect once, but connection-less sockets can connect multiple times to change the default address. If the connect call needs to do network I/O it will block, unless non-blocking I/O is enabled. Then %G_IO_ERROR_PENDING is returned and the user can be notified of the connection finishing by waiting for the G_IO_OUT condition. The result of the connection must then be checked with g_socket_check_connect_result().
- **@p** `address` is a #GSocketAddress specifying the remote address..
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `%TRUE` if connected, %FALSE on error..
- **connection\_factory\_create\_connection** ()
> Creates a #GSocketConnection subclass of the right type for @socket.
- **@r** `a` #GSocketConnection.
- **create\_source** (`string condition, object cancellable`)
> Creates a #GSource that can be attached to a %GMainContext to monitor for the availability of the specified @condition on the socket. The #GSource keeps a reference to the @socket. The callback on the source is of the #GSocketSourceFunc type. It is meaningless to specify %G_IO_ERR or %G_IO_HUP in @condition; these conditions will always be reported output if they are true. @cancellable if not %NULL can be used to cancel the source, which will cause the source to trigger, reporting the current condition (which is likely 0 unless cancellation happened at the same time as a condition change). You can check for this in the callback using g_cancellable_is_cancelled(). If @socket has a timeout set, and it is reached before @condition occurs, the source will then trigger anyway, reporting %G_IO_IN or %G_IO_OUT depending on @condition. However, @socket will have been marked as having had a timeout, and so the next #GSocket I/O method you call will then fail with a %G_IO_ERROR_TIMED_OUT.
- **@p** `condition` is a #GIOCondition mask to monitor.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `a` newly allocated %GSource, free with g_source_unref()..
- **get\_available\_bytes** ()
> Get the amount of data pending in the OS input buffer, without blocking. If @socket is a UDP or SCTP socket, this will return the size of just the next packet, even if additional packets are buffered after that one. Note that on Windows, this function is rather inefficient in the UDP case, and so if you know any plausible upper bound on the size of the incoming packet, it is better to just do a g_socket_receive() with a buffer of that size, rather than calling g_socket_get_available_bytes() first and then doing a receive of exactly the right size.
- **@r** `the` number of bytes that can be read from the socket without blocking or truncating, or -1 on error..
- **get\_blocking** ()
> Gets the blocking mode of the socket. For details on blocking I/O, see g_socket_set_blocking().
- **@r** `%TRUE` if blocking I/O is used, %FALSE otherwise..
- **get\_broadcast** ()
> Gets the broadcast setting on @socket; if %TRUE, it is possible to send packets to broadcast addresses.
- **@r** `the` broadcast setting on @socket.
- **get\_credentials** ()
> Returns the credentials of the foreign process connected to this socket, if any (e.g. it is only supported for %G_SOCKET_FAMILY_UNIX sockets). If this operation isn't supported on the OS, the method fails with the %G_IO_ERROR_NOT_SUPPORTED error. On Linux this is implemented by reading the %SO_PEERCRED option on the underlying socket. This method can be expected to be available on the following platforms: - Linux since GLib 2.26 - OpenBSD since GLib 2.30 - Solaris, Illumos and OpenSolaris since GLib 2.40 - NetBSD since GLib 2.42 - macOS, tvOS, iOS since GLib 2.66 Other ways to obtain credentials from a foreign peer includes the #GUnixCredentialsMessage type and g_unix_connection_send_credentials() / g_unix_connection_receive_credentials() functions.
- **@r** `%NULL` if @error is set, otherwise a #GCredentials object that must be freed with g_object_unref()..
- **get\_family** ()
> Gets the socket family of the socket.
- **@r** `a` #GSocketFamily.
- **get\_fd** ()
> Returns the underlying OS socket object. On unix this is a socket file descriptor, and on Windows this is a Winsock2 SOCKET handle. This may be useful for doing platform specific or otherwise unusual operations on the socket.
- **@r** `the` file descriptor of the socket..
- **get\_keepalive** ()
> Gets the keepalive mode of the socket. For details on this, see g_socket_set_keepalive().
- **@r** `%TRUE` if keepalive is active, %FALSE otherwise..
- **get\_listen\_backlog** ()
> Gets the listen backlog setting of the socket. For details on this, see g_socket_set_listen_backlog().
- **@r** `the` maximum number of pending connections..
- **get\_local\_address** ()
> Try to get the local address of a bound socket. This is only useful if the socket has been bound to a local address, either explicitly or implicitly when connecting.
- **@r** `a` #GSocketAddress or %NULL on error. Free the returned object with g_object_unref()..
- **get\_multicast\_loopback** ()
> Gets the multicast loopback setting on @socket; if %TRUE (the default), outgoing multicast packets will be looped back to multicast listeners on the same host.
- **@r** `the` multicast loopback setting on @socket.
- **get\_multicast\_ttl** ()
> Gets the multicast time-to-live setting on @socket; see g_socket_set_multicast_ttl() for more details.
- **@r** `the` multicast time-to-live setting on @socket.
- **get\_option** (`int level, int optname`)
> Gets the value of an integer-valued option on @socket, as with getsockopt(). (If you need to fetch a non-integer-valued option, you will need to call getsockopt() directly.) The [`<gio/gnetworking.h>`](networking.html) header pulls in system headers that will define most of the standard/portable socket options. For unusual socket protocols or platform-dependent options, you may need to include additional headers. Note that even for socket options that are a single byte in size, @value is still a pointer to a #gint variable, not a #guchar; g_socket_get_option() will handle the conversion internally.
- **@p** `level` is the "API level" of the option (eg, `SOL_SOCKET`).
- **@p** `optname` is the "name" of the option (eg, `SO_BROADCAST`).
- **@p** `value` is return location for the option value.
- **@r** `success` or failure. On failure, @error will be set, and the system error value (`errno` or WSAGetLastError()) will still be set to the result of the getsockopt() call..
- **get\_protocol** ()
> Gets the socket protocol id the socket was created with. In case the protocol is unknown, -1 is returned.
- **@r** `a` protocol id, or -1 if unknown.
- **get\_remote\_address** ()
> Try to get the remote address of a connected socket. This is only useful for connection oriented sockets that have been connected.
- **@r** `a` #GSocketAddress or %NULL on error. Free the returned object with g_object_unref()..
- **get\_socket\_type** ()
> Gets the socket type of the socket.
- **@r** `a` #GSocketType.
- **get\_timeout** ()
> Gets the timeout setting of the socket. For details on this, see g_socket_set_timeout().
- **@r** `the` timeout in seconds.
- **get\_ttl** ()
> Gets the unicast time-to-live setting on @socket; see g_socket_set_ttl() for more details.
- **@r** `the` time-to-live setting on @socket.
- **is\_closed** ()
> Checks whether a socket is closed.
- **@r** `%TRUE` if socket is closed, %FALSE otherwise.
- **is\_connected** ()
> Check whether the socket is connected. This is only useful for connection-oriented sockets. If using g_socket_shutdown(), this function will return %TRUE until the socket has been shut down for reading and writing. If you do a non-blocking connect, this function will not return %TRUE until after you call g_socket_check_connect_result().
- **@r** `%TRUE` if socket is connected, %FALSE otherwise..
- **join\_multicast\_group** (`object group, bool source_specific, string iface`)
> Registers @socket to receive multicast messages sent to @group. @socket must be a %G_SOCKET_TYPE_DATAGRAM socket, and must have been bound to an appropriate interface and port with g_socket_bind(). If @iface is %NULL, the system will automatically pick an interface to bind to based on
- **@group.** `If` @source_specific is %TRUE, source-specific multicast as defined in RFC 4604 is used. Note that on older platforms this may fail with a %G_IO_ERROR_NOT_SUPPORTED error. To bind to a given source-specific multicast address, use g_socket_join_multicast_group_ssm() instead.
- **@p** `group` is a #GInetAddress specifying the group address to join..
- **@p** `source_specific` is %TRUE if source-specific multicast should be used.
- **@p** `iface` is Name of the interface to use, or %NULL.
- **@r** `%TRUE` on success, %FALSE on error..
- **join\_multicast\_group\_ssm** (`object group, object source_specific, string iface`)
> Registers @socket to receive multicast messages sent to @group. @socket must be a %G_SOCKET_TYPE_DATAGRAM socket, and must have been bound to an appropriate interface and port with g_socket_bind(). If @iface is %NULL, the system will automatically pick an interface to bind to based on
- **@group.** `If` @source_specific is not %NULL, use source-specific multicast as defined in RFC 4604. Note that on older platforms this may fail with a %G_IO_ERROR_NOT_SUPPORTED error. Note that this function can be called multiple times for the same @group with different @source_specific in order to receive multicast packets from more than one source.
- **@p** `group` is a #GInetAddress specifying the group address to join..
- **@p** `source_specific` is a #GInetAddress specifying the source-specific multicast address or %NULL to ignore..
- **@p** `iface` is Name of the interface to use, or %NULL.
- **@r** `%TRUE` on success, %FALSE on error..
- **leave\_multicast\_group** (`object group, bool source_specific, string iface`)
> Removes @socket from the multicast group defined by @group, @iface, and
- **@source_specific** `(which` must all have the same values they had when you joined the group). @socket remains bound to its address and port, and can still receive unicast messages after calling this. To unbind to a given source-specific multicast address, use g_socket_leave_multicast_group_ssm() instead.
- **@p** `group` is a #GInetAddress specifying the group address to leave..
- **@p** `source_specific` is %TRUE if source-specific multicast was used.
- **@p** `iface` is Interface used.
- **@r** `%TRUE` on success, %FALSE on error..
- **leave\_multicast\_group\_ssm** (`object group, object source_specific, string iface`)
> Removes @socket from the multicast group defined by @group, @iface, and
- **@source_specific** `(which` must all have the same values they had when you joined the group). @socket remains bound to its address and port, and can still receive unicast messages after calling this.
- **@p** `group` is a #GInetAddress specifying the group address to leave..
- **@p** `source_specific` is a #GInetAddress specifying the source-specific multicast address or %NULL to ignore..
- **@p** `iface` is Name of the interface to use, or %NULL.
- **@r** `%TRUE` on success, %FALSE on error..
- **listen** ()
> Marks the socket as a server socket, i.e. a socket that is used to accept incoming requests using g_socket_accept(). Before calling this the socket must be bound to a local address using g_socket_bind(). To set the maximum amount of outstanding clients, use g_socket_set_listen_backlog().
- **@r** `%TRUE` on success, %FALSE on error..
- **receive** (`int size, object cancellable`)
> Receive data (up to @size bytes) from a socket. This is mainly used by connection-oriented sockets; it is identical to g_socket_receive_from() with @address set to %NULL. For %G_SOCKET_TYPE_DATAGRAM and %G_SOCKET_TYPE_SEQPACKET sockets, g_socket_receive() will always read either 0 or 1 complete messages from the socket. If the received message is too large to fit in @buffer, then the data beyond @size bytes will be discarded, without any explicit indication that this has occurred. For %G_SOCKET_TYPE_STREAM sockets, g_socket_receive() can return any number of bytes, up to @size. If more than @size bytes have been received, the additional data will be returned in future calls to g_socket_receive(). If the socket is in blocking mode the call will block until there is some data to receive, the connection is closed, or there is an error. If there is no data available and the socket is in non-blocking mode, a %G_IO_ERROR_WOULD_BLOCK error will be returned. To be notified when data is available, wait for the %G_IO_IN condition. On error -1 is returned and @error is set accordingly.
- **@p** `buffer` is a buffer to read data into (which should be at least @size bytes long)..
- **@p** `size` is the number of bytes you want to read from the socket.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes read, or 0 if the connection was closed by the peer, or -1 on error.
- **receive\_bytes** (`int size, int timeout_us, object cancellable`)
> Receives data (up to @size bytes) from a socket. This function is a variant of [method@Gio.Socket.receive] which returns a [struct@GLib.Bytes] rather than a plain buffer. Pass `-1` to @timeout_us to block indefinitely until data is received (or the connection is closed, or there is an error). Pass `0` to use the default timeout from [property@Gio.Socket:timeout], or pass a positive number to wait for that many microseconds for data before returning `G_IO_ERROR_TIMED_OUT`.
- **@p** `size` is the number of bytes you want to read from the socket.
- **@p** `timeout_us` is the timeout to wait for, in microseconds, or `-1` to block indefinitely.
- **@p** `cancellable` is a %GCancellable, or `NULL`.
- **@r** `a` bytes buffer containing the received bytes, or `NULL` on error.
- **receive\_bytes\_from** (`int size, int timeout_us, object cancellable`)
> Receive data (up to @size bytes) from a socket. This function is a variant of [method@Gio.Socket.receive_from] which returns a [struct@GLib.Bytes] rather than a plain buffer. If @address is non-%NULL then @address will be set equal to the source address of the received packet. The @address is owned by the caller. Pass `-1` to @timeout_us to block indefinitely until data is received (or the connection is closed, or there is an error). Pass `0` to use the default timeout from [property@Gio.Socket:timeout], or pass a positive number to wait for that many microseconds for data before returning `G_IO_ERROR_TIMED_OUT`.
- **@p** `address` is return location for a #GSocketAddress.
- **@p** `size` is the number of bytes you want to read from the socket.
- **@p** `timeout_us` is the timeout to wait for, in microseconds, or `-1` to block indefinitely.
- **@p** `cancellable` is a #GCancellable, or `NULL`.
- **@r** `a` bytes buffer containing the received bytes, or `NULL` on error.
- **receive\_from** (`int size, object cancellable`)
> Receive data (up to @size bytes) from a socket. If @address is non-%NULL then @address will be set equal to the source address of the received packet. @address is owned by the caller. See g_socket_receive() for additional information.
- **@p** `address` is a pointer to a #GSocketAddress pointer, or %NULL.
- **@p** `buffer` is a buffer to read data into (which should be at least @size bytes long)..
- **@p** `size` is the number of bytes you want to read from the socket.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes read, or 0 if the connection was closed by the peer, or -1 on error.
- **receive\_message** (`list vectors, int flags, object cancellable`)
> Receive data from a socket. For receiving multiple messages, see g_socket_receive_messages(); for easier use, see g_socket_receive() and g_socket_receive_from(). If @address is non-%NULL then @address will be set equal to the source address of the received packet. @address is owned by the caller. @vector must point to an array of #GInputVector structs and @num_vectors must be the length of this array. These structs describe the buffers that received data will be scattered into. If @num_vectors is -1, then @vectors is assumed to be terminated by a #GInputVector with a %NULL buffer pointer. As a special case, if @num_vectors is 0 (in which case, @vectors may of course be %NULL), then a single byte is received and discarded. This is to facilitate the common practice of sending a single '\0' byte for the purposes of transferring ancillary data.
- **@messages,** `if` non-%NULL, will be set to point to a newly-allocated array of #GSocketControlMessage instances or %NULL if no such messages was received. These correspond to the control messages received from the kernel, one #GSocketControlMessage per message from the kernel. This array is %NULL-terminated and must be freed by the caller using g_free() after calling g_object_unref() on each element. If @messages is %NULL, any control messages received will be discarded. @num_messages, if non-%NULL, will be set to the number of control messages received. If both @messages and @num_messages are non-%NULL, then @num_messages gives the number of #GSocketControlMessage instances in @messages (ie: not including the %NULL terminator). @flags is an in/out parameter. The commonly available arguments for this are available in the #GSocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too (and g_socket_receive_message() may pass system-specific flags out). Flags passed in to the parameter affect the receive operation; flags returned out of it are relevant to the specific returned message. As with g_socket_receive(), data may be discarded if
- **@socket** `is` %G_SOCKET_TYPE_DATAGRAM or %G_SOCKET_TYPE_SEQPACKET and you do not provide enough buffer space to read a complete message. You can pass %G_SOCKET_MSG_PEEK in @flags to peek at the current message without removing it from the receive queue, but there is no portable way to find out the length of the message other than by reading it into a sufficiently-large buffer. If the socket is in blocking mode the call will block until there is some data to receive, the connection is closed, or there is an error. If there is no data available and the socket is in non-blocking mode, a %G_IO_ERROR_WOULD_BLOCK error will be returned. To be notified when data is available, wait for the %G_IO_IN condition. On error -1 is returned and @error is set accordingly.
- **@p** `address` is a pointer to a #GSocketAddress pointer, or %NULL.
- **@p** `vectors` is an array of #GInputVector structs.
- **@p** `num_vectors` is the number of elements in @vectors, or -1.
- **@p** `messages` is a pointer which may be filled with an array of #GSocketControlMessages, or %NULL.
- **@p** `num_messages` is a pointer which will be filled with the number of elements in @messages, or %NULL.
- **@p** `flags` is a pointer to an int containing #GSocketMsgFlags flags, which may additionally contain [other platform specific flags](http://man7.org/linux/man-pages/man2/recv.2.html).
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes read, or 0 if the connection was closed by the peer, or -1 on error.
- **receive\_messages** (`list messages, int flags, object cancellable`)
> Receive multiple data messages from @socket in one go. This is the most complicated and fully-featured version of this call. For easier use, see g_socket_receive(), g_socket_receive_from(), and g_socket_receive_message(). @messages must point to an array of #GInputMessage structs and @num_messages must be the length of this array. Each #GInputMessage contains a pointer to an array of #GInputVector structs describing the buffers that the data received in each message will be written to. Using multiple #GInputVectors is more memory-efficient than manually copying data out of a single buffer to multiple sources, and more system-call-efficient than making multiple calls to g_socket_receive(), such as in scenarios where a lot of data packets need to be received (e.g. high-bandwidth video streaming over RTP/UDP). @flags modify how all messages are received. The commonly available arguments for this are available in the #GSocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too. These flags affect the overall receive operation. Flags affecting individual messages are returned in #GInputMessage.flags. The other members of #GInputMessage are treated as described in its documentation. If #GSocket:blocking is %TRUE the call will block until @num_messages have been received, or the end of the stream is reached. If #GSocket:blocking is %FALSE the call will return up to @num_messages without blocking, or %G_IO_ERROR_WOULD_BLOCK if no messages are queued in the operating system to be received. In blocking mode, if #GSocket:timeout is positive and is reached before any messages are received, %G_IO_ERROR_TIMED_OUT is returned, otherwise up to @num_messages are returned. (Note: This is effectively the behaviour of `MSG_WAITFORONE` with recvmmsg().) To be notified when messages are available, wait for the %G_IO_IN condition. Note though that you may still receive %G_IO_ERROR_WOULD_BLOCK from g_socket_receive_messages() even if you were previously notified of a %G_IO_IN condition. If the remote peer closes the connection, any messages queued in the operating system will be returned, and subsequent calls to g_socket_receive_messages() will return 0 (with no error set). On error -1 is returned and @error is set accordingly. An error will only be returned if zero messages could be received; otherwise the number of messages successfully received before the error will be returned.
- **@p** `messages` is an array of #GInputMessage structs.
- **@p** `num_messages` is the number of elements in @messages.
- **@p** `flags` is an int containing #GSocketMsgFlags flags for the overall operation, which may additionally contain [other platform specific flags](http://man7.org/linux/man-pages/man2/recv.2.html).
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `number` of messages received, or -1 on error. Note that the number of messages received may be smaller than @num_messages if in non-blocking mode, if the peer closed the connection, or if @num_messages was larger than `UIO_MAXIOV` (1024), in which case the caller may re-try to receive the remaining messages..
- **receive\_with\_blocking** (`int size, bool blocking, object cancellable`)
> This behaves exactly the same as g_socket_receive(), except that the choice of blocking or non-blocking behavior is determined by the
- **@blocking** `argument` rather than by @socket's properties.
- **@p** `buffer` is a buffer to read data into (which should be at least @size bytes long)..
- **@p** `size` is the number of bytes you want to read from the socket.
- **@p** `blocking` is whether to do blocking or non-blocking I/O.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes read, or 0 if the connection was closed by the peer, or -1 on error.
- **send** (`list buffer, object cancellable`)
> Tries to send @size bytes from @buffer on the socket. This is mainly used by connection-oriented sockets; it is identical to g_socket_send_to() with @address set to %NULL. If the socket is in blocking mode the call will block until there is space for the data in the socket queue. If there is no space available and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error will be returned. To be notified when space is available, wait for the %G_IO_OUT condition. Note though that you may still receive %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously notified of a %G_IO_OUT condition. (On Windows in particular, this is very common due to the way the underlying APIs work.) On error -1 is returned and @error is set accordingly.
- **@p** `buffer` is the buffer containing the data to send..
- **@p** `size` is the number of bytes to send.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes written (which may be less than @size), or -1 on error.
- **send\_message** (`object address, list vectors, list messages, int flags, object cancellable`)
> Send data to @address on @socket. For sending multiple messages see g_socket_send_messages(); for easier use, see g_socket_send() and g_socket_send_to(). If @address is %NULL then the message is sent to the default receiver (set by g_socket_connect()). @vectors must point to an array of #GOutputVector structs and @num_vectors must be the length of this array. (If @num_vectors is -1, then @vectors is assumed to be terminated by a #GOutputVector with a %NULL buffer pointer.) The #GOutputVector structs describe the buffers that the sent data will be gathered from. Using multiple #GOutputVectors is more memory-efficient than manually copying data from multiple sources into a single buffer, and more network-efficient than making multiple calls to g_socket_send().
- **@messages,** `if` non-%NULL, is taken to point to an array of @num_messages #GSocketControlMessage instances. These correspond to the control messages to be sent on the socket. If @num_messages is -1 then @messages is treated as a %NULL-terminated array. @flags modify how the message is sent. The commonly available arguments for this are available in the #GSocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too. If the socket is in blocking mode the call will block until there is space for the data in the socket queue. If there is no space available and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error will be returned. To be notified when space is available, wait for the %G_IO_OUT condition. Note though that you may still receive %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously notified of a %G_IO_OUT condition. (On Windows in particular, this is very common due to the way the underlying APIs work.) The sum of the sizes of each #GOutputVector in vectors must not be greater than %G_MAXSSIZE. If the message can be larger than this, then it is mandatory to use the g_socket_send_message_with_timeout() function. On error -1 is returned and @error is set accordingly.
- **@p** `address` is a #GSocketAddress, or %NULL.
- **@p** `vectors` is an array of #GOutputVector structs.
- **@p** `num_vectors` is the number of elements in @vectors, or -1.
- **@p** `messages` is a pointer to an array of #GSocketControlMessages, or %NULL..
- **@p** `num_messages` is number of elements in @messages, or -1..
- **@p** `flags` is an int containing #GSocketMsgFlags flags, which may additionally contain [other platform specific flags](http://man7.org/linux/man-pages/man2/recv.2.html).
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes written (which may be less than @size), or -1 on error.
- **send\_message\_with\_timeout** (`object address, list vectors, list messages, int flags, int timeout_us, object cancellable`)
> This behaves exactly the same as g_socket_send_message(), except that the choice of timeout behavior is determined by the @timeout_us argument rather than by @socket's properties. On error %G_POLLABLE_RETURN_FAILED is returned and @error is set accordingly, or if the socket is currently not writable %G_POLLABLE_RETURN_WOULD_BLOCK is returned. @bytes_written will contain 0 in both cases.
- **@p** `address` is a #GSocketAddress, or %NULL.
- **@p** `vectors` is an array of #GOutputVector structs.
- **@p** `num_vectors` is the number of elements in @vectors, or -1.
- **@p** `messages` is a pointer to an array of #GSocketControlMessages, or %NULL..
- **@p** `num_messages` is number of elements in @messages, or -1..
- **@p** `flags` is an int containing #GSocketMsgFlags flags, which may additionally contain [other platform specific flags](http://man7.org/linux/man-pages/man2/recv.2.html).
- **@p** `timeout_us` is the maximum time (in microseconds) to wait, or -1.
- **@p** `bytes_written` is location to store the number of bytes that were written to the socket.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `%G_POLLABLE_RETURN_OK` if all data was successfully written, %G_POLLABLE_RETURN_WOULD_BLOCK if the socket is currently not writable, or %G_POLLABLE_RETURN_FAILED if an error happened and @error is set..
- **send\_messages** (`list messages, int flags, object cancellable`)
> Send multiple data messages from @socket in one go. This is the most complicated and fully-featured version of this call. For easier use, see g_socket_send(), g_socket_send_to(), and g_socket_send_message().
- **@messages** `must` point to an array of #GOutputMessage structs and
- **@num_messages** `must` be the length of this array. Each #GOutputMessage contains an address to send the data to, and a pointer to an array of #GOutputVector structs to describe the buffers that the data to be sent for each message will be gathered from. Using multiple #GOutputVectors is more memory-efficient than manually copying data from multiple sources into a single buffer, and more network-efficient than making multiple calls to g_socket_send(). Sending multiple messages in one go avoids the overhead of making a lot of syscalls in scenarios where a lot of data packets need to be sent (e.g. high-bandwidth video streaming over RTP/UDP), or where the same data needs to be sent to multiple recipients.
- **@flags** `modify` how the message is sent. The commonly available arguments for this are available in the #GSocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too. If the socket is in blocking mode the call will block until there is space for all the data in the socket queue. If there is no space available and the socket is in non-blocking mode a %G_IO_ERROR_WOULD_BLOCK error will be returned if no data was written at all, otherwise the number of messages sent will be returned. To be notified when space is available, wait for the %G_IO_OUT condition. Note though that you may still receive %G_IO_ERROR_WOULD_BLOCK from g_socket_send() even if you were previously notified of a %G_IO_OUT condition. (On Windows in particular, this is very common due to the way the underlying APIs work.) On error -1 is returned and @error is set accordingly. An error will only be returned if zero messages could be sent; otherwise the number of messages successfully sent before the error will be returned.
- **@p** `messages` is an array of #GOutputMessage structs.
- **@p** `num_messages` is the number of elements in @messages.
- **@p** `flags` is an int containing #GSocketMsgFlags flags, which may additionally contain [other platform specific flags](http://man7.org/linux/man-pages/man2/recv.2.html).
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `number` of messages sent, or -1 on error. Note that the number of messages sent may be smaller than @num_messages if the socket is non-blocking or if @num_messages was larger than UIO_MAXIOV (1024), in which case the caller may re-try to send the remaining messages..
- **send\_to** (`object address, list buffer, object cancellable`)
> Tries to send @size bytes from @buffer to @address. If @address is %NULL then the message is sent to the default receiver (set by g_socket_connect()). See g_socket_send() for additional information.
- **@p** `address` is a #GSocketAddress, or %NULL.
- **@p** `buffer` is the buffer containing the data to send..
- **@p** `size` is the number of bytes to send.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes written (which may be less than @size), or -1 on error.
- **send\_with\_blocking** (`list buffer, bool blocking, object cancellable`)
> This behaves exactly the same as g_socket_send(), except that the choice of blocking or non-blocking behavior is determined by the @blocking argument rather than by @socket's properties.
- **@p** `buffer` is the buffer containing the data to send..
- **@p** `size` is the number of bytes to send.
- **@p** `blocking` is whether to do blocking or non-blocking I/O.
- **@p** `cancellable` is a %GCancellable or %NULL.
- **@r** `Number` of bytes written (which may be less than @size), or -1 on error.
- **set\_blocking** (`bool blocking`)
> Sets the blocking mode of the socket. In blocking mode all operations (which don’t take an explicit blocking parameter) block until they succeed or there is an error. In non-blocking mode all functions return results immediately or with a %G_IO_ERROR_WOULD_BLOCK error. All sockets are created in blocking mode. However, note that the platform level socket is always non-blocking, and blocking mode is a GSocket level feature.
- **@p** `blocking` is Whether to use blocking I/O or not..
- **@r** `None.`
- **set\_broadcast** (`bool broadcast`)
> Sets whether @socket should allow sending to broadcast addresses. This is %FALSE by default.
- **@p** `broadcast` is whether @socket should allow sending to broadcast addresses.
- **@r** `None.`
- **set\_keepalive** (`bool keepalive`)
> Sets or unsets the %SO_KEEPALIVE flag on the underlying socket. When this flag is set on a socket, the system will attempt to verify that the remote socket endpoint is still present if a sufficiently long period of time passes with no data being exchanged. If the system is unable to verify the presence of the remote endpoint, it will automatically close the connection. This option is only functional on certain kinds of sockets. (Notably, %G_SOCKET_PROTOCOL_TCP sockets.) The exact time between pings is system- and protocol-dependent, but will normally be at least two hours. Most commonly, you would set this flag on a server socket if you want to allow clients to remain idle for long periods of time, but also want to ensure that connections are eventually garbage-collected if clients crash or become unreachable.
- **@p** `keepalive` is Value for the keepalive flag.
- **@r** `None.`
- **set\_listen\_backlog** (`int backlog`)
> Sets the maximum number of outstanding connections allowed when listening on this socket. If more clients than this are connecting to the socket and the application is not handling them on time then the new connections will be refused. Note that this must be called before g_socket_listen() and has no effect if called after that.
- **@p** `backlog` is the maximum number of pending connections..
- **@r** `None.`
- **set\_multicast\_loopback** (`bool loopback`)
> Sets whether outgoing multicast packets will be received by sockets listening on that multicast address on the same host. This is %TRUE by default.
- **@p** `loopback` is whether @socket should receive messages sent to its multicast groups from the local host.
- **@r** `None.`
- **set\_multicast\_ttl** (`int ttl`)
> Sets the time-to-live for outgoing multicast datagrams on @socket. By default, this is 1, meaning that multicast packets will not leave the local network.
- **@p** `ttl` is the time-to-live value for all multicast datagrams on @socket.
- **@r** `None.`
- **set\_option** (`int level, int optname, int value`)
> Sets the value of an integer-valued option on @socket, as with setsockopt(). (If you need to set a non-integer-valued option, you will need to call setsockopt() directly.) The [`<gio/gnetworking.h>`](networking.html) header pulls in system headers that will define most of the standard/portable socket options. For unusual socket protocols or platform-dependent options, you may need to include additional headers.
- **@p** `level` is the "API level" of the option (eg, `SOL_SOCKET`).
- **@p** `optname` is the "name" of the option (eg, `SO_BROADCAST`).
- **@p** `value` is the value to set the option to.
- **@r** `success` or failure. On failure, @error will be set, and the system error value (`errno` or WSAGetLastError()) will still be set to the result of the setsockopt() call..
- **set\_timeout** (`int timeout`)
> Sets the time in seconds after which I/O operations on @socket will time out if they have not yet completed. On a blocking socket, this means that any blocking #GSocket operation will time out after @timeout seconds of inactivity, returning %G_IO_ERROR_TIMED_OUT. On a non-blocking socket, calls to g_socket_condition_wait() will also fail with %G_IO_ERROR_TIMED_OUT after the given time. Sources created with g_socket_create_source() will trigger after @timeout seconds of inactivity, with the requested condition set, at which point calling g_socket_receive(), g_socket_send(), g_socket_check_connect_result(), etc, will fail with %G_IO_ERROR_TIMED_OUT. If @timeout is 0 (the default), operations will never time out on their own. Note that if an I/O operation is interrupted by a signal, this may cause the timeout to be reset.
- **@p** `timeout` is the timeout for @socket, in seconds, or 0 for none.
- **@r** `None.`
- **set\_ttl** (`int ttl`)
> Sets the time-to-live for outgoing unicast packets on @socket. By default the platform-specific default value is used.
- **@p** `ttl` is the time-to-live value for all unicast packets on @socket.
- **@r** `None.`
- **shutdown** (`bool shutdown_read, bool shutdown_write`)
> Shut down part or all of a full-duplex connection. If @shutdown_read is %TRUE then the receiving side of the connection is shut down, and further reading is disallowed. If @shutdown_write is %TRUE then the sending side of the connection is shut down, and further writing is disallowed. It is allowed for both @shutdown_read and @shutdown_write to be %TRUE. One example where it is useful to shut down only one side of a connection is graceful disconnect for TCP connections where you close the sending side, then wait for the other side to close the connection, thus ensuring that the other side saw all sent data.
- **@p** `shutdown_read` is whether to shut down the read side.
- **@p** `shutdown_write` is whether to shut down the write side.
- **@r** `%TRUE` on success, %FALSE on error.
- **speaks\_ipv4** ()
> Checks if a socket is capable of speaking IPv4. IPv4 sockets are capable of speaking IPv4. On some operating systems and under some combinations of circumstances IPv6 sockets are also capable of speaking IPv4. See RFC 3493 section 3.7 for more information. No other types of sockets are currently considered as being capable of speaking IPv4.
- **@r** `%TRUE` if this socket can be used with IPv4..
## class: GSocketMeta
[1650:14] `static` **extends: object**
Generated metadata helpers for `Socket` class surfaces.
#### Methods
- **properties** ()
> Returns property metadata for `Socket`.
- **@r** `A` list.
## class: GSocketCtors
[1623:14] `static` **extends: object**
Alternate constructors for `GSocket`. Usage:
`GSocketCtors.<name>(...)`. The primary constructor lives
directly on `GSocket`.
#### Methods
- **newFromFd** (`int fd`)
> Creates a new #GSocket from a native file descriptor or winsock SOCKET handle. This reads all the settings from the file descriptor so that all properties should work. Note that the file descriptor will be set to non-blocking mode, independent on the blocking mode of the #GSocket. On success, the returned #GSocket takes ownership of @fd. On failure, the caller must close @fd themselves. Since GLib 2.46, it is no longer a fatal error to call this on a non-socket descriptor. Instead, a GError will be set with code %G_IO_ERROR_FAILED
- **@p** `fd` is a native socket file descriptor..
- **@r** `A` new `GSocket`.
