Memory-managed wrapper type.

Type class for types which can be safely cast to Socket, for instance with toSocket.

Cast to Socket, for types for which this is known to be safe. For general casts, use castTo.

Accept incoming connections on a connection-based socket. This removes the first outstanding connection request from the listening socket and creates a Socket object for it.

The socket must be bound to a local address with socketBind and must be listening for incoming connections (socketListen).

If there are no outstanding connections then the operation will block or return IOErrorEnumWouldBlock if non-blocking I/O is enabled. To be notified of an incoming connection, wait for the IOConditionIn condition.

Since: 2.22

When a socket is created it is attached to an address family, but it doesn't have an address in this family. socketBind 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 socketListen and socketAccept ). 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 allowReuse controls the setting of the SO_REUSEADDR socket option; normally it should be True for server sockets (sockets that you will eventually call socketAccept on), and False for client sockets. (Failing to set this flag on a server socket may cause socketBind to return IOErrorEnumAddressInUse if the server program is stopped and then immediately restarted.)

If socket is a UDP socket, then allowReuse 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.)

Since: 2.22

Checks and resets the pending connect error for the socket. This is used to check for errors when socketConnect is used in non-blocking mode.

Since: 2.22

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 IOErrorEnumClosed. 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 IOConditionIn 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 socketShutdown with only the shutdownWrite 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 socketClose. (This is what TcpConnection does if you call tcpConnectionSetGracefulDisconnect. But of course, this only works if the client will close its connection after the server does.)

Since: 2.22

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 IOErrorEnumWouldBlock even immediately after socketConditionCheck has claimed that the socket is ready for writing. Rather than calling socketConditionCheck 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 IOErrorEnumWouldBlock.

It is meaningless to specify IOConditionErr or IOConditionHup in condition; these conditions will always be set in the output if they are true.

This call never blocks.

Since: 2.22

Waits for up to timeoutUs 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 timeoutUs (or the socket's Socket:timeout) is reached before the condition is met, then False is returned and error, if non-Nothing, is set to the appropriate value (IOErrorEnumCancelled or IOErrorEnumTimedOut).

If you don't want a timeout, use socketConditionWait. (Alternatively, you can pass -1 for timeoutUs.)

Note that although timeoutUs is in microseconds for consistency with other GLib APIs, this function actually only has millisecond resolution, and the behavior is undefined if timeoutUs is not an exact number of milliseconds.

Since: 2.32

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-Nothing, is set to the appropriate value (IOErrorEnumCancelled or IOErrorEnumTimedOut).

See also socketConditionTimedWait.

Since: 2.22

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 socketSend 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 IOErrorEnumPending 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 socketCheckConnectResult.

Since: 2.22

Creates a SocketConnection subclass of the right type for socket.

Since: 2.22

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 socketReceive with a buffer of that size, rather than calling socketGetAvailableBytes first and then doing a receive of exactly the right size.

Since: 2.32

Gets the blocking mode of the socket. For details on blocking I/O, see socketSetBlocking.

Since: 2.22

Gets the broadcast setting on socket; if True, it is possible to send packets to broadcast addresses.

Since: 2.32

Returns the credentials of the foreign process connected to this socket, if any (e.g. it is only supported for SocketFamilyUnix sockets).

If this operation isn't supported on the OS, the method fails with the IOErrorEnumNotSupported 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 UnixCredentialsMessage type and unixConnectionSendCredentials / unixConnectionReceiveCredentials functions.

Since: 2.26

Gets the socket family of the socket.

Since: 2.22

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.

Since: 2.22

Gets the keepalive mode of the socket. For details on this, see socketSetKeepalive.

Since: 2.22

Gets the listen backlog setting of the socket. For details on this, see socketSetListenBacklog.

Since: 2.22

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.

Since: 2.22

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.

Since: 2.32

Gets the multicast time-to-live setting on socket; see socketSetMulticastTtl for more details.

Since: 2.32

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>` 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; socketGetOption will handle the conversion internally.

Since: 2.36

Gets the socket protocol id the socket was created with. In case the protocol is unknown, -1 is returned.

Since: 2.22

Try to get the remote address of a connected socket. This is only useful for connection oriented sockets that have been connected.

Since: 2.22

Gets the socket type of the socket.

Since: 2.22

Gets the timeout setting of the socket. For details on this, see socketSetTimeout.

Since: 2.26

Gets the unicast time-to-live setting on socket; see socketSetTtl for more details.

Since: 2.32

Checks whether a socket is closed.

Since: 2.22

Check whether the socket is connected. This is only useful for connection-oriented sockets.

If using socketShutdown, 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 socketCheckConnectResult.

Since: 2.22

Registers socket to receive multicast messages sent to group. socket must be a SocketTypeDatagram socket, and must have been bound to an appropriate interface and port with socketBind.

If iface is Nothing, the system will automatically pick an interface to bind to based on group.

If sourceSpecific is True, source-specific multicast as defined in RFC 4604 is used. Note that on older platforms this may fail with a IOErrorEnumNotSupported error.

To bind to a given source-specific multicast address, use socketJoinMulticastGroupSsm instead.

Since: 2.32

Registers socket to receive multicast messages sent to group. socket must be a SocketTypeDatagram socket, and must have been bound to an appropriate interface and port with socketBind.

If iface is Nothing, the system will automatically pick an interface to bind to based on group.

If sourceSpecific is not Nothing, use source-specific multicast as defined in RFC 4604. Note that on older platforms this may fail with a IOErrorEnumNotSupported error.

Note that this function can be called multiple times for the same group with different sourceSpecific in order to receive multicast packets from more than one source.

Since: 2.56

Removes socket from the multicast group defined by group, iface, and sourceSpecific (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 socketLeaveMulticastGroupSsm instead.

Since: 2.32

Removes socket from the multicast group defined by group, iface, and sourceSpecific (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.

Since: 2.56

Marks the socket as a server socket, i.e. a socket that is used to accept incoming requests using socketAccept.

Before calling this the socket must be bound to a local address using socketBind.

To set the maximum amount of outstanding clients, use socketSetListenBacklog.

Since: 2.22

Creates a new Socket with the defined family, type and protocol. If protocol is 0 (SocketProtocolDefault) 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. SocketProtocol 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 SocketProtocol if you know the protocol number used for it.

Since: 2.22

Creates a new Socket 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 Socket.

On success, the returned Socket 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 IOErrorEnumFailed

Since: 2.22

Receive data (up to size bytes) from a socket. This is mainly used by connection-oriented sockets; it is identical to socketReceiveFrom with address set to Nothing.

For SocketTypeDatagram and SocketTypeSeqpacket sockets, socketReceive 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 SocketTypeStream sockets, socketReceive 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 socketReceive.

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 IOErrorEnumWouldBlock error will be returned. To be notified when data is available, wait for the IOConditionIn condition.

On error -1 is returned and error is set accordingly.

Since: 2.22

Receives data (up to size bytes) from a socket.

This function is a variant of socketReceive which returns a Bytes rather than a plain buffer.

Pass -1 to timeoutUs 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 Socket:timeout, or pass a positive number to wait for that many microseconds for data before returning G_IO_ERROR_TIMED_OUT.

Since: 2.80

Receive data (up to size bytes) from a socket.

This function is a variant of socketReceiveFrom which returns a Bytes rather than a plain buffer.

If address is non-Nothing then address will be set equal to the source address of the received packet.

The address is owned by the caller.

Pass -1 to timeoutUs 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 Socket:timeout, or pass a positive number to wait for that many microseconds for data before returning G_IO_ERROR_TIMED_OUT.

Since: 2.80

Receive data (up to size bytes) from a socket.

If address is non-Nothing then address will be set equal to the source address of the received packet. address is owned by the caller.

See socketReceive for additional information.

Since: 2.22

Receive data from a socket. For receiving multiple messages, see socketReceiveMessages; for easier use, see socketReceive and socketReceiveFrom.

If address is non-Nothing 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 InputVector structs and numVectors must be the length of this array. These structs describe the buffers that received data will be scattered into. If numVectors is -1, then vectors is assumed to be terminated by a InputVector with a Nothing buffer pointer.

As a special case, if numVectors is 0 (in which case, vectors may of course be Nothing), 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-Nothing, will be set to point to a newly-allocated array of SocketControlMessage instances or Nothing if no such messages was received. These correspond to the control messages received from the kernel, one SocketControlMessage per message from the kernel. This array is Nothing-terminated and must be freed by the caller using free after calling objectUnref on each element. If messages is Nothing, any control messages received will be discarded.

numMessages, if non-Nothing, will be set to the number of control messages received.

If both messages and numMessages are non-Nothing, then numMessages gives the number of SocketControlMessage instances in messages (ie: not including the Nothing terminator).

flags is an in/out parameter. The commonly available arguments for this are available in the SocketMsgFlags 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 socketReceiveMessage 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 socketReceive, data may be discarded if socket is SocketTypeDatagram or SocketTypeSeqpacket and you do not provide enough buffer space to read a complete message. You can pass SocketMsgFlagsPeek 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 IOErrorEnumWouldBlock error will be returned. To be notified when data is available, wait for the IOConditionIn condition.

On error -1 is returned and error is set accordingly.

Since: 2.22

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 socketReceive, socketReceiveFrom, and socketReceiveMessage.

messages must point to an array of InputMessage structs and numMessages must be the length of this array. Each InputMessage contains a pointer to an array of InputVector 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 socketReceive, 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 SocketMsgFlags 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 InputMessage.flags.

The other members of InputMessage are treated as described in its documentation.

If Socket:blocking is True the call will block until numMessages have been received, or the end of the stream is reached.

If Socket:blocking is False the call will return up to numMessages without blocking, or IOErrorEnumWouldBlock if no messages are queued in the operating system to be received.

In blocking mode, if Socket:timeout is positive and is reached before any messages are received, IOErrorEnumTimedOut is returned, otherwise up to numMessages are returned. (Note: This is effectively the behaviour of MSG_WAITFORONE with recvmmsg().)

To be notified when messages are available, wait for the IOConditionIn condition. Note though that you may still receive IOErrorEnumWouldBlock from socketReceiveMessages even if you were previously notified of a IOConditionIn condition.

If the remote peer closes the connection, any messages queued in the operating system will be returned, and subsequent calls to socketReceiveMessages 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.

Since: 2.48

This behaves exactly the same as socketReceive, except that the choice of blocking or non-blocking behavior is determined by the blocking argument rather than by socket's properties.

Since: 2.26

Tries to send size bytes from buffer on the socket. This is mainly used by connection-oriented sockets; it is identical to socketSendTo with address set to Nothing.

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 IOErrorEnumWouldBlock error will be returned. To be notified when space is available, wait for the IOConditionOut condition. Note though that you may still receive IOErrorEnumWouldBlock from socketSend even if you were previously notified of a IOConditionOut 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.

Since: 2.22

Send data to address on socket. For sending multiple messages see socketSendMessages; for easier use, see socketSend and socketSendTo.

If address is Nothing then the message is sent to the default receiver (set by socketConnect).

vectors must point to an array of OutputVector structs and numVectors must be the length of this array. (If numVectors is -1, then vectors is assumed to be terminated by a OutputVector with a Nothing buffer pointer.) The OutputVector 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 socketSend.

messages, if non-Nothing, is taken to point to an array of numMessages SocketControlMessage instances. These correspond to the control messages to be sent on the socket. If numMessages is -1 then messages is treated as a Nothing-terminated array.

flags modify how the message is sent. The commonly available arguments for this are available in the SocketMsgFlags 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 IOErrorEnumWouldBlock error will be returned. To be notified when space is available, wait for the IOConditionOut condition. Note though that you may still receive IOErrorEnumWouldBlock from socketSend even if you were previously notified of a IOConditionOut condition. (On Windows in particular, this is very common due to the way the underlying APIs work.)

The sum of the sizes of each OutputVector in vectors must not be greater than G_MAXSSIZE. If the message can be larger than this, then it is mandatory to use the socketSendMessageWithTimeout function.

On error -1 is returned and error is set accordingly.

Since: 2.22

This behaves exactly the same as socketSendMessage, except that the choice of timeout behavior is determined by the timeoutUs argument rather than by socket's properties.

On error PollableReturnFailed is returned and error is set accordingly, or if the socket is currently not writable PollableReturnWouldBlock is returned. bytesWritten will contain 0 in both cases.

Since: 2.60

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 socketSend, socketSendTo, and socketSendMessage.

messages must point to an array of OutputMessage structs and numMessages must be the length of this array. Each OutputMessage contains an address to send the data to, and a pointer to an array of OutputVector 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 socketSend. 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 SocketMsgFlags 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 IOErrorEnumWouldBlock 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 IOConditionOut condition. Note though that you may still receive IOErrorEnumWouldBlock from socketSend even if you were previously notified of a IOConditionOut 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.

Since: 2.44