# Struct std::net::UdpSocket 1.0.0 [−] [src]

    pub struct UdpSocket(_);

A UDP socket.

After creating a `UdpSocket` by `bind`ing it to a socket address, data can be sent to and received from any other socket address.

Although UDP is a connectionless protocol, this implementation provides an interface to set an address where data should be sent and received from. After setting a remote address with `connect`, data can be sent to and received from that address with `send` and `recv`.

As stated in the User Datagram Protocol's specification in IETF RFC 768, UDP is an unordered, unreliable protocol; refer to `TcpListener` and `TcpStream` for TCP primitives.

# Examples

    use std::net::UdpSocket;

    {
        let mut socket = UdpSocket::bind("127.0.0.1:34254")?;

        // Receives a single datagram message on the socket. If `buf` is too small to hold
        // the message, it will be cut off.
        let mut buf = [0; 10];
        let (amt, src) = socket.recv_from(&mut buf)?;

        // Redeclare `buf` as slice of the received data and send reverse data back to origin.
        let buf = &mut buf[..amt];
        buf.reverse();
        socket.send_to(buf, &src)?;
    } // the socket is closed hereRun

## Methods

### `impl UdpSocket`
[src]

#### `pub fn bind<A: ToSocketAddrs>(addr: A) -> Result<UdpSocket>`
[src]

Creates a UDP socket from the given address.

The address type can be any implementor of `ToSocketAddrs` trait. See its documentation for concrete examples.

If `addr` yields multiple addresses, `bind` will be attempted with each of the addresses until one succeeds and returns the socket. If none of the addresses succeed in creating a socket, the error returned from the last attempt (the last address) is returned.

# Examples

Create a UDP socket bound to `127.0.0.1:3400`:

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");Run

Create a UDP socket bound to `127.0.0.1:3400`. If the socket cannot be bound to that address, create a UDP socket bound to `127.0.0.1:3401`:

    use std::net::{SocketAddr, UdpSocket};

    let addrs = [
        SocketAddr::from(([127, 0, 0, 1], 3400)),
        SocketAddr::from(([127, 0, 0, 1], 3401)),
    ];
    let socket = UdpSocket::bind(&addrs[..]).expect("couldn't bind to address");Run

#### `pub fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>`
[src]

Receives a single datagram message on the socket. On success, returns the number of bytes read and the origin.

The function must be called with valid byte array `buf` of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    let mut buf = [0; 10];
    let (number_of_bytes, src_addr) = socket.recv_from(&mut buf)
                                            .expect("Didn't receive data");
    let filled_buf = &mut buf[..number_of_bytes];Run

#### `pub fn peek_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>`
1.18.0
[src]

Receives a single datagram message on the socket, without removing it from the queue. On success, returns the number of bytes read and the origin.

The function must be called with valid byte array `buf` of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

Successive calls return the same data. This is accomplished by passing `MSG_PEEK` as a flag to the underlying `recvfrom` system call.

Do not use this function to implement busy waiting, instead use `libc::poll` to synchronize IO events on one or more sockets.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    let mut buf = [0; 10];
    let (number_of_bytes, src_addr) = socket.peek_from(&mut buf)
                                            .expect("Didn't receive data");
    let filled_buf = &mut buf[..number_of_bytes];Run

#### `pub fn send_to<A: ToSocketAddrs>(&self, buf: &[u8], addr: A) -> Result<usize>`
[src]

Sends data on the socket to the given address. On success, returns the number of bytes written.

Address type can be any implementor of `ToSocketAddrs` trait. See its documentation for concrete examples.

It is possible for `addr` to yield multiple addresses, but `send_to` will only send data to the first address yielded by `addr`.

This will return an error when the IP version of the local socket does not match that returned from `ToSocketAddrs`.

See https://github.com/rust-lang/rust/issues/34202 for more details.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.send_to(&[0; 10], "127.0.0.1:4242").expect("couldn't send data");Run

#### `pub fn local_addr(&self) -> Result<SocketAddr>`
[src]

Returns the socket address that this socket was created from.

# Examples

    use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, UdpSocket};

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    assert_eq!(socket.local_addr().unwrap(),
               SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 34254)));Run

#### `pub fn try_clone(&self) -> Result<UdpSocket>`
[src]

Creates a new independently owned handle to the underlying socket.

The returned `UdpSocket` is a reference to the same socket that this object references. Both handles will read and write the same port, and options set on one socket will be propagated to the other.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    let socket_clone = socket.try_clone().expect("couldn't clone the socket");Run

#### `pub fn set_read_timeout(&self, dur: Option<Duration>) -> Result<()>`
1.4.0
[src]

Sets the read timeout to the timeout specified.

If the value specified is `None`, then `read` calls will block indefinitely. It is an error to pass the zero `Duration` to this method.

# Note

Platforms may return a different error code whenever a read times out as a result of setting this option. For example Unix typically returns an error of the kind `WouldBlock`, but Windows may return `TimedOut`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_read_timeout(None).expect("set_read_timeout call failed");Run

#### `pub fn set_write_timeout(&self, dur: Option<Duration>) -> Result<()>`
1.4.0
[src]

Sets the write timeout to the timeout specified.

If the value specified is `None`, then `write` calls will block indefinitely. It is an error to pass the zero `Duration` to this method.

# Note

Platforms may return a different error code whenever a write times out as a result of setting this option. For example Unix typically returns an error of the kind `WouldBlock`, but Windows may return `TimedOut`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_write_timeout(None).expect("set_write_timeout call failed");Run

#### `pub fn read_timeout(&self) -> Result<Option<Duration>>`
1.4.0
[src]

Returns the read timeout of this socket.

If the timeout is `None`, then `read` calls will block indefinitely.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_read_timeout(None).expect("set_read_timeout call failed");
    assert_eq!(socket.read_timeout().unwrap(), None);Run

#### `pub fn write_timeout(&self) -> Result<Option<Duration>>`
1.4.0
[src]

Returns the write timeout of this socket.

If the timeout is `None`, then `write` calls will block indefinitely.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_write_timeout(None).expect("set_write_timeout call failed");
    assert_eq!(socket.write_timeout().unwrap(), None);Run

#### `pub fn set_broadcast(&self, broadcast: bool) -> Result<()>`
1.9.0
[src]

Sets the value of the `SO_BROADCAST` option for this socket.

When enabled, this socket is allowed to send packets to a broadcast address.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_broadcast(false).expect("set_broadcast call failed");Run

#### `pub fn broadcast(&self) -> Result<bool>`
1.9.0
[src]

Gets the value of the `SO_BROADCAST` option for this socket.

For more information about this option, see `set_broadcast`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_broadcast(false).expect("set_broadcast call failed");
    assert_eq!(socket.broadcast().unwrap(), false);Run

#### `pub fn set_multicast_loop_v4(&self, multicast_loop_v4: bool) -> Result<()>`
1.9.0
[src]

Sets the value of the `IP_MULTICAST_LOOP` option for this socket.

If enabled, multicast packets will be looped back to the local socket. Note that this may not have any affect on IPv6 sockets.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");Run

#### `pub fn multicast_loop_v4(&self) -> Result<bool>`
1.9.0
[src]

Gets the value of the `IP_MULTICAST_LOOP` option for this socket.

For more information about this option, see `set_multicast_loop_v4`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_multicast_loop_v4(false).expect("set_multicast_loop_v4 call failed");
    assert_eq!(socket.multicast_loop_v4().unwrap(), false);Run

#### `pub fn set_multicast_ttl_v4(&self, multicast_ttl_v4: u32) -> Result<()>`
1.9.0
[src]

Sets the value of the `IP_MULTICAST_TTL` option for this socket.

Indicates the time-to-live value of outgoing multicast packets for this socket. The default value is 1 which means that multicast packets don't leave the local network unless explicitly requested.

Note that this may not have any affect on IPv6 sockets.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");Run

#### `pub fn multicast_ttl_v4(&self) -> Result<u32>`
1.9.0
[src]

Gets the value of the `IP_MULTICAST_TTL` option for this socket.

For more information about this option, see `set_multicast_ttl_v4`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_multicast_ttl_v4(42).expect("set_multicast_ttl_v4 call failed");
    assert_eq!(socket.multicast_ttl_v4().unwrap(), 42);Run

#### `pub fn set_multicast_loop_v6(&self, multicast_loop_v6: bool) -> Result<()>`
1.9.0
[src]

Sets the value of the `IPV6_MULTICAST_LOOP` option for this socket.

Controls whether this socket sees the multicast packets it sends itself. Note that this may not have any affect on IPv4 sockets.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");Run

#### `pub fn multicast_loop_v6(&self) -> Result<bool>`
1.9.0
[src]

Gets the value of the `IPV6_MULTICAST_LOOP` option for this socket.

For more information about this option, see `set_multicast_loop_v6`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_multicast_loop_v6(false).expect("set_multicast_loop_v6 call failed");
    assert_eq!(socket.multicast_loop_v6().unwrap(), false);Run

#### `pub fn set_ttl(&self, ttl: u32) -> Result<()>`
1.9.0
[src]

Sets the value for the `IP_TTL` option on this socket.

This value sets the time-to-live field that is used in every packet sent from this socket.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_ttl(42).expect("set_ttl call failed");Run

#### `pub fn ttl(&self) -> Result<u32>`
1.9.0
[src]

Gets the value of the `IP_TTL` option for this socket.

For more information about this option, see `set_ttl`.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.set_ttl(42).expect("set_ttl call failed");
    assert_eq!(socket.ttl().unwrap(), 42);Run

#### `pub fn join_multicast_v4(
&self,
multiaddr: &Ipv4Addr,
interface: &Ipv4Addr
) -> Result<()>`
1.9.0
[src]

Executes an operation of the `IP_ADD_MEMBERSHIP` type.

This function specifies a new multicast group for this socket to join. The address must be a valid multicast address, and `interface` is the address of the local interface with which the system should join the multicast group. If it's equal to `INADDR_ANY` then an appropriate interface is chosen by the system.

#### `pub fn join_multicast_v6(
&self,
multiaddr: &Ipv6Addr,
interface: u32
) -> Result<()>`
1.9.0
[src]

Executes an operation of the `IPV6_ADD_MEMBERSHIP` type.

This function specifies a new multicast group for this socket to join. The address must be a valid multicast address, and `interface` is the index of the interface to join/leave (or 0 to indicate any interface).

#### `pub fn leave_multicast_v4(
&self,
multiaddr: &Ipv4Addr,
interface: &Ipv4Addr
) -> Result<()>`
1.9.0
[src]

Executes an operation of the `IP_DROP_MEMBERSHIP` type.

For more information about this option, see `join_multicast_v4`.

#### `pub fn leave_multicast_v6(
&self,
multiaddr: &Ipv6Addr,
interface: u32
) -> Result<()>`
1.9.0
[src]

Executes an operation of the `IPV6_DROP_MEMBERSHIP` type.

For more information about this option, see `join_multicast_v6`.

#### `pub fn take_error(&self) -> Result<Option<Error>>`
1.9.0
[src]

Get the value of the `SO_ERROR` option on this socket.

This will retrieve the stored error in the underlying socket, clearing the field in the process. This can be useful for checking errors between calls.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    match socket.take_error() {
        Ok(Some(error)) => println!("UdpSocket error: {:?}", error),
        Ok(None) => println!("No error"),
        Err(error) => println!("UdpSocket.take_error failed: {:?}", error),
    }Run

#### `pub fn connect<A: ToSocketAddrs>(&self, addr: A) -> Result<()>`
1.9.0
[src]

Connects this UDP socket to a remote address, allowing the `send` and `recv` syscalls to be used to send data and also applies filters to only receive data from the specified address.

If `addr` yields multiple addresses, `connect` will be attempted with each of the addresses until the underlying OS function returns no error. Note that usually, a successful `connect` call does not specify that there is a remote server listening on the port, rather, such an error would only be detected after the first send. If the OS returns an error for each of the specified addresses, the error returned from the last connection attempt (the last address) is returned.

# Examples

Create a UDP socket bound to `127.0.0.1:3400` and connect the socket to `127.0.0.1:8080`:

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");
    socket.connect("127.0.0.1:8080").expect("connect function failed");Run

Unlike in the TCP case, passing an array of addresses to the `connect` function of a UDP socket is not a useful thing to do: The OS will be unable to determine whether something is listening on the remote address without the application sending data.

#### `pub fn send(&self, buf: &[u8]) -> Result<usize>`
1.9.0
[src]

Sends data on the socket to the remote address to which it is connected.

The `connect` method will connect this socket to a remote address. This method will fail if the socket is not connected.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.connect("127.0.0.1:8080").expect("connect function failed");
    socket.send(&[0, 1, 2]).expect("couldn't send message");Run

#### `pub fn recv(&self, buf: &mut [u8]) -> Result<usize>`
1.9.0
[src]

Receives a single datagram message on the socket from the remote address to which it is connected. On success, returns the number of bytes read.

The function must be called with valid byte array `buf` of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

The `connect` method will connect this socket to a remote address. This method will fail if the socket is not connected.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.connect("127.0.0.1:8080").expect("connect function failed");
    let mut buf = [0; 10];
    match socket.recv(&mut buf) {
        Ok(received) => println!("received {} bytes {:?}", received, &buf[..received]),
        Err(e) => println!("recv function failed: {:?}", e),
    }Run

#### `pub fn peek(&self, buf: &mut [u8]) -> Result<usize>`
1.18.0
[src]

Receives single datagram on the socket from the remote address to which it is connected, without removing the message from input queue. On success, returns the number of bytes peeked.

The function must be called with valid byte array `buf` of sufficient size to hold the message bytes. If a message is too long to fit in the supplied buffer, excess bytes may be discarded.

Successive calls return the same data. This is accomplished by passing `MSG_PEEK` as a flag to the underlying `recv` system call.

Do not use this function to implement busy waiting, instead use `libc::poll` to synchronize IO events on one or more sockets.

The `connect` method will connect this socket to a remote address. This method will fail if the socket is not connected.

# Errors

This method will fail if the socket is not connected. The `connect` method will connect this socket to a remote address.

# Examples

    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:34254").expect("couldn't bind to address");
    socket.connect("127.0.0.1:8080").expect("connect function failed");
    let mut buf = [0; 10];
    match socket.peek(&mut buf) {
        Ok(received) => println!("received {} bytes", received),
        Err(e) => println!("peek function failed: {:?}", e),
    }Run

#### `pub fn set_nonblocking(&self, nonblocking: bool) -> Result<()>`
1.9.0
[src]

Moves this UDP socket into or out of nonblocking mode.

This will result in `recv`, `recv_from`, `send`, and `send_to` operations becoming nonblocking, i.e. immediately returning from their calls. If the IO operation is successful, `Ok` is returned and no further action is required. If the IO operation could not be completed and needs to be retried, an error with kind `io::ErrorKind::WouldBlock` is returned.

On Unix platforms, calling this method corresponds to calling `fcntl` `FIONBIO`. On Windows calling this method corresponds to calling `ioctlsocket` `FIONBIO`.

# Examples

Create a UDP socket bound to `127.0.0.1:7878` and read bytes in nonblocking mode:

    use std::io;
    use std::net::UdpSocket;

    let socket = UdpSocket::bind("127.0.0.1:7878").unwrap();
    socket.set_nonblocking(true).unwrap();

    let mut buf = [0; 10];
    let (num_bytes_read, _) = loop {
        match socket.recv_from(&mut buf) {
            Ok(n) => break n,
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                // wait until network socket is ready, typically implemented
                // via platform-specific APIs such as epoll or IOCP
                wait_for_fd();
            }
            Err(e) => panic!("encountered IO error: {}", e),
        }
    };
    println!("bytes: {:?}", &buf[..num_bytes_read]);Run

## Trait Implementations

### `impl Debug for UdpSocket`
[src]

#### `fn fmt(&self, f: &mut Formatter) -> Result`
[src]

Formats the value using the given formatter. Read more

### `impl AsRawFd for UdpSocket`
[src]

#### `fn as_raw_fd(&self) -> RawFd`
[src]

This is supported on Unix only.

Extracts the raw file descriptor. Read more

### `impl FromRawFd for UdpSocket`
1.1.0
[src]

#### `unsafe fn from_raw_fd(fd: RawFd) -> UdpSocket`
[src]

This is supported on Unix only.

Constructs a new instance of `Self` from the given raw file descriptor. Read more

### `impl IntoRawFd for UdpSocket`
1.4.0
[src]

#### `fn into_raw_fd(self) -> RawFd`
[src]

This is supported on Unix only.

Consumes this object, returning the raw underlying file descriptor. Read more

### `impl AsRawSocket for UdpSocket`
[src]

#### `fn as_raw_socket(&self) -> RawSocket`
[src]

This is supported on Windows only.

Extracts the underlying raw socket from this object.

### `impl FromRawSocket for UdpSocket`
1.1.0
[src]

#### `unsafe fn from_raw_socket(sock: RawSocket) -> UdpSocket`
[src]

This is supported on Windows only.

Creates a new I/O object from the given raw socket. Read more

### `impl IntoRawSocket for UdpSocket`
1.4.0
[src]

#### `fn into_raw_socket(self) -> RawSocket`
[src]

This is supported on Windows only.

Consumes this object, returning the raw underlying socket. Read more

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