DatagramBasedT

A GDatagramBased is a networking interface for representing datagram-based communications. It is a more or less direct mapping of the core parts of the BSD socket API in a portable GObject interface. It is implemented by gio.Socket, which wraps the UNIX socket API on UNIX and winsock2 on Windows.

GDatagramBased is entirely platform independent, and is intended to be used alongside higher-level networking APIs such as gio.IOStream

It uses vectored scatter/gather I/O by default, allowing for many messages to be sent or received in a single call. Where possible, implementations of the interface should take advantage of vectored I/O to minimise processing or system calls. For example, gio.Socket uses recvmmsg() and sendmmsg() where possible. Callers should take advantage of scatter/gather I/O (the use of multiple buffers per message) to avoid unnecessary copying of data to assemble or disassemble a message.

Each GDatagramBased operation has a timeout parameter which may be negative for blocking behaviour, zero for non-blocking behaviour, or positive for timeout behaviour. A blocking operation blocks until finished or there is an error. A non-blocking operation will return immediately with a G_IO_ERROR_WOULD_BLOCK error if it cannot make progress. A timeout operation will block until the operation is complete or the timeout expires; if the timeout expires it will return what progress it made, or G_IO_ERROR_TIMED_OUT if no progress was made. To know when a call would successfully run you can call g_datagram_based_condition_check() or g_datagram_based_condition_wait(). You can also use g_datagram_based_create_source() and attach it to a glib.MainContext to get callbacks when I/O is possible.

When running a non-blocking operation 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.

As with gio.Socket, GDatagramBaseds can be either connection oriented (for example, SCTP) or connectionless (for example, UDP). GDatagramBaseds must be datagram-based, not stream-based. The interface does not cover connection establishment — use methods on the underlying type to establish a connection before sending and receiving data through the GDatagramBased API. For connectionless socket types the target/source address is specified or received in each I/O operation.

Like most other APIs in GLib, GDatagramBased is not inherently thread safe. To use a GDatagramBased concurrently from multiple threads, you must implement your own locking.

Members

Functions

conditionCheck
GIOCondition conditionCheck(GIOCondition condition)

Checks on the readiness of datagram_based to perform operations. The operations specified in condition are checked for and masked against the currently-satisfied conditions on datagram_based. The result is returned.

conditionWait
bool conditionWait(GIOCondition condition, long timeout, Cancellable cancellable)

Waits for up to timeout microseconds for condition to become true on datagram_based. If the condition is met, TRUE is returned.

createSource
Source createSource(GIOCondition condition, Cancellable cancellable)

Creates a glib.Source that can be attached to a glib.MainContext to monitor for the availability of the specified condition on the GDatagramBased The glib.Source keeps a reference to the datagram_based.

getDatagramBasedStruct
GDatagramBased* getDatagramBasedStruct(bool transferOwnership = false)

Get the main Gtk struct

receiveMessages
int receiveMessages(GInputMessage[] messages, int flags, long timeout, Cancellable cancellable)

Receive one or more data messages from datagram_based in one go.

sendMessages
int sendMessages(GOutputMessage[] messages, int flags, long timeout, Cancellable cancellable)

Send one or more data messages from datagram_based in one go.

Meta

Since

2.48