sendto() -- Sockets Function (libsocket)

Send a message to a socket
#include <sys/socket.h>
#include <sys/types.h>
int send(socket, message, length, flags, addr, alen)
int socket; char *message; int length, flags;
sockaddr_t *addr; int alen;

The  function sendto()  sends a  message to a  socket.  Unlike  the related
function sendto(), it works regardless of whether the socket is connected.

socket is  the socket to  which the messages  are sent.  It  must have been
created by the function socket(). buffer points to the chunk of memory into
which the  message is to be  written; length gives the  amount of allocated
memory to  which buffer points.  If from is  not NULL, sendto() initializes
it to  the the source address  of the message.  It  initializes alen to the
size of the buffer associated with  address, and modifies it upon return to
the size of the address stored there.

flags ORs together either or both of the following flags:

MSG_OOB
     Send ``out-of-band''  data on sockets  that support this  notion.  The
     underlying protocol must also support out-of-band data.

MSG_DONTROUTE
     The socket  turned on for the  duration of the operation.   It is used
     only by diagnostic or routing programs.

If  all goes  well,  sendto() returns  the  number of  bytes  it sent.   If
something goes wrong, it returns -1  and sets errno to one of the following
values:

EAGAIN
     If socket has no buffer space available, sendto() normally waits until
     space  becomes available  (which  is a  blocking operation).   socket,
     however, is marked as non-blocking.

EBADF
     socket does not identify a valid socket.

EINTR
     A signal interrupted sendto() before it could send any data.

EMSGSIZE
     socket requires  that message be sent atomically,  and the message was
     too long.

ENOMEM
     Insufficient user memory was available to complete the operation.

ENOTSOCK
     socket describes a file, not a socket.

EPROTO
     A protocol error has occurred.

See Also

connect(),
libsocket,
recv(),
send(),
socket()

Notes

At present,  the COHERENT implementation  of sendto() always  behaves as if
address were initialized to NULL.

© 2012 by Stephen A. Ness