Function send [src]

Transmit a message to another socket. The send call may be used only when the socket is in a connected state (so that the intended recipient is known). The only difference between send and write is the presence of flags. With a zero flags argument, send is equivalent to write. Also, the following call send(sockfd, buf, len, flags); is equivalent to sendto(sockfd, buf, len, flags, NULL, 0); There is no indication of failure to deliver. When the message does not fit into the send buffer of the socket, send normally blocks, unless the socket has been placed in nonblocking I/O mode. In nonblocking mode it would fail with SendError.WouldBlock. The select call may be used to determine when it is possible to send more data.

Prototype

pub fn send( sockfd: socket_t, buf: []const u8, flags: u32, ) SendError!usize

Parameters

sockfd: socket_tThe file descriptor of the sending socket.

buf: []const u8flags: u32

Possible Errors

AccessDenied

(For UNIX domain sockets, which are identified by pathname) Write permission is denied on the destination socket file, or search permission is denied for one of the directories the path prefix. (See path_resolution(7).) (For UDP sockets) An attempt was made to send to a network/broadcast address as though it was a unicast address.

BrokenPipe

The local end has been shut down on a connection oriented socket. In this case, the process will also receive a SIGPIPE unless MSG.NOSIGNAL is set.

ConnectionResetByPeer

Connection reset by peer.

FastOpenAlreadyInProgress

Another Fast Open is already in progress.

FileDescriptorNotASocket

MessageTooBig

The socket type requires that message be sent atomically, and the size of the message to be sent made this impossible. The message is not transmitted.

NetworkSubsystemFailed

The local network interface used to reach the destination is down.

NetworkUnreachable

Network is unreachable.

SystemResources

The output queue for a network interface was full. This generally indicates that the interface has stopped sending, but may be caused by transient congestion. (Normally, this does not occur in Linux. Packets are just silently dropped when a device queue overflows.) This is also caused when there is not enough kernel memory available.

Unexpected UnexpectedError

The Operating System returned an undocumented error code.

This error is in theory not possible, but it would be better to handle this error than to invoke undefined behavior.

When this error code is observed, it usually means the Zig Standard Library needs a small patch to add the error code to the error set for the respective function.

WouldBlock

The socket is marked nonblocking and the requested operation would block, and there is no global event loop configured. It's also possible to get this error under the following condition: (Internet domain datagram sockets) The socket referred to by sockfd had not previously been bound to an address and, upon attempting to bind it to an ephemeral port, it was determined that all port numbers in the ephemeral port range are currently in use. See the discussion of /proc/sys/net/ipv4/ip_local_port_range in ip(7).

Source

  pub fn send(
    /// The file descriptor of the sending socket.
    sockfd: socket_t,
    buf: []const u8,
    flags: u32,
) SendError!usize {
    return sendto(sockfd, buf, flags, null, 0) catch |err| switch (err) {
        error.AddressFamilyNotSupported => unreachable,
        error.SymLinkLoop => unreachable,
        error.NameTooLong => unreachable,
        error.FileNotFound => unreachable,
        error.NotDir => unreachable,
        error.NetworkUnreachable => unreachable,
        error.AddressNotAvailable => unreachable,
        error.SocketNotConnected => unreachable,
        error.UnreachableAddress => unreachable,
        error.ConnectionRefused => unreachable,
        else => |e| return e,
    };
}  