This function can be used on sockets to send data to named
    sockets. The data in the msg buffer is sent to the socket whose
    address is specified in the to argument, and the address of
    socket s is provided to the receiving socket. The receiving
    socket gets the data using the read(), recv(),  recvfrom(), or
    recvmsg() function.
    Normally the sendto() function blocks if there is no space for
    the incoming data in the buffer. It waits until the buffer space
    becomes available. If the socket is set to nonblocking and there
    is no space for the data, the sendto() function fails with the
    EWOULDBLOCK error.
    If the message is too large to be sent in one piece, and the
    socket type is SOCK_DGRAM, which requires that messages be sent
    in one piece, sendto() fails with the EMSGSIZE error.
    If the address specified is a INADDR_BROADCAST address, then the
    SO_BROADCAST socket option must have been set and the process
    must have SYSPRV or BYPASS privilege for the I/O operation to
    succeed.
    A success return from the sendto() does not guarantee that
    the data has been received by the peer. All errors (except
    EWOULDBLOCK) are detected locally. To determine when it is
    possible to send more data, use the select() function.
    Related Functions
    See also read(), recv(),  recvfrom(), recvmsg(), socket(),  and
    getsockopt().