send(3XNET) X/Open Networking Services Library Functions send(3XNET)NAMEsend - send a message on a socket
SYNOPSIS
cc [ flag ... ] file ... -lxnet [ library ... ]
#include <sys/socket.h>
ssize_t send(int socket, const void *buffer, size_t length, int flags);
PARAMETERS
socket Specifies the socket file descriptor.
buffer Points to the buffer containing the message to send.
length Specifies the length of the message in bytes.
flags Specifies the type of message transmission. Values of
this argument are formed by logically OR'ing zero or
more of the following flags:
MSG_EOR Terminates a record (if sup‐
ported by the protocol)
MSG_OOB Sends out-of-band data on sock‐
ets that support out-of-band
communications. The signifi‐
cance and semantics of out-of-
band data are protocol-spe‐
cific.
DESCRIPTION
The send() function initiates transmission of a message from the speci‐
fied socket to its peer. The send() function sends a message only when
the socket is connected (including when the peer of a connectionless
socket has been set via connect(3XNET)).
The length of the message to be sent is specified by the length argu‐
ment. If the message is too long to pass through the underlying proto‐
col, send() fails and no data is transmitted.
Successful completion of a call to send() does not guarantee delivery
of the message. A return value of −1 indicates only locally-detected
errors.
If space is not available at the sending socket to hold the message to
be transmitted and the socket file descriptor does not have O_NONBLOCK
set, send() blocks until space is available. If space is not available
at the sending socket to hold the message to be transmitted and the
socket file descriptor does have O_NONBLOCK set, send() will fail. The
select(3C) and poll(2) functions can be used to determine when it is
possible to send more data.
The socket in use may require the process to have appropriate privi‐
leges to use the send() function.
USAGE
The send() function is identical to sendto(3XNET) with a null pointer
dest_len argument, and to write() if no flags are used.
RETURN VALUES
Upon successful completion, send() returns the number of bytes sent.
Otherwise, −1 is returned and errno is set to indicate the error.
ERRORS
The send() function will fail if:
EAGAIN The socket's file descriptor is marked O_NON‐
EWOULDBLOCK BLOCK and the requested operation would block.
EBADF The socket argument is not a valid file
descriptor.
ECONNRESET A connection was forcibly closed by a peer.
EDESTADDRREQ The socket is not connection-mode and no peer
address is set.
EFAULT The buffer parameter can not be accessed.
EINTR A signal interrupted send() before any data was
transmitted.
EMSGSIZE The message is too large be sent all at once,
as the socket requires.
ENOTCONN The socket is not connected or otherwise has
not had the peer prespecified.
ENOTSOCK The socket argument does not refer to a socket.
EOPNOTSUPP The socket argument is associated with a socket
that does not support one or more of the values
set in flags.
EPIPE The socket is shut down for writing, or the
socket is connection-mode and is no longer con‐
nected. In the latter case, and if the socket
is of type SOCK_STREAM, the SIGPIPE signal is
generated to the calling thread.
The send() function may fail if:
EACCES The calling process does not have the appropri‐
ate privileges.
EIO An I/O error occurred while reading from or
writing to the file system.
ENETDOWN The local interface used to reach the destina‐
tion is down.
ENETUNREACH No route to the network is present.
ENOBUFS Insufficient resources were available in the
system to perform the operation.
ENOSR There were insufficient STREAMS resources
available for the operation to complete.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOconnect(3XNET), getsockopt(3XNET), poll(2), recv(3XNET),
recvfrom(3XNET), recvmsg(3XNET), select(3C), sendmsg(3XNET),
sendto(3XNET), setsockopt(3XNET), shutdown(3XNET), socket(3XNET),
attributes(5), standards(5)SunOS 5.10 1 Nov 2003 send(3XNET)
