SEND(3N-SVR4)       RISC/os Reference Manual        SEND(3N-SVR4)



NAME
     send, sendto, sendmsg - send a message from a socket

SYNOPSIS
     #include <sys/types.h>
     #include <sys/socket.h>

     int send(s, msg, len, flags)
     int s;
     char *msg;
     int len, flags;

     int sendto(s, msg, len, flags, to, tolen)
     int s;
     char *msg;
     int len, flags;
     struct sockaddr *to;
     int tolen;

     int sendmsg(s, msg, flags)
     int s;
     struct msghdr *msg;
     int flags;

DESCRIPTION
     s is a socket created with socket(3N).  send(), sendto(),
     and sendmsg() are used to transmit a message to another
     socket.  send() may be used only when the socket is in a
     connected state, while sendto() and sendmsg() may be used at
     any time.

     The address of the target is given by to with tolen specify-
     ing its size.  The length of the message is given by len.
     If the message is too long to pass atomically through the
     underlying protocol, then the error EMSGSIZE is returned,
     and the message is not transmitted.

     No indication of failure to deliver is implicit in a send().
     Return values of -1 indicate some locally detected errors.

     If no buffer space is available at the socket to hold the
     message to be transmitted, then send() normally blocks,
     unless the socket has been placed in non-blocking I/O mode
     (see fcntl(2)).  The select() call may be used to determine
     when it is possible to send more data.

     The flags parameter is formed by ORing one or more of the
     following:

     MSG_OOB   Send out-of-band data on sockets that support this
               notion. The underlying protocol must also support
               out-of-band data.  Currently, only SOCK_STREAM



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SEND(3N-SVR4)       RISC/os Reference Manual        SEND(3N-SVR4)



               sockets created in the AF_INET address family sup-
               port out-of-band data.

     MSG_DONTROUTE
               The SO_DONTROUTE option is turned on for the dura-
               tion of the operation.  It is used only by diag-
               nostic or routing programs.

     See recv(3N) for a description of the msghdr structure.

RETURN VALUE
     These calls return the number of bytes sent, or -1 if an
     error occurred.

ERRORS
     The calls fail if:

     EBADF               s is an invalid descriptor.

     ENOTSOCK            s is a descriptor for a file, not a
                         socket.

     EINVAL              tolen is not the size of a valid address
                         for the specified address family.

     EINTR               The operation was interrupted by
                         delivery of a signal before any data
                         could be buffered to be sent.

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

     EWOULDBLOCK         The socket is marked non-blocking and
                         the requested operation would block.

     ENOMEM              There was insufficient user memory
                         available for the operation to complete.

     ENOSR               There were insufficient STREAMS
                         resources available for the operation to
                         complete.

SEE ALSO
     connect(3N), fcntl(2), getsockopt(3N), recv(3N), socket(3N),
     write(2).









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