SEND (2)
send a message from a socket
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
int send(int s , const void * msg , size_t len ,
int flags );
int sendto(int s , const void * msg , size_t len ,
int flags , const struct sockaddr * to , socklen_t tolen );
int sendmsg(int s , const struct msghdr * msg ,
int flags );
DESCRIPTION
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
specifying its size. The length of the message is given by
len .
If the message is too long to pass atomically through the
underlying protocol, the error
EMSGSIZE
is returned, and the message is not transmitted.
No indication of failure to deliver is implicit in a
send .
Locally detected errors are indicated by a return value of -1.
When the message does not fit into the send buffer of the socket,
send
normally blocks, unless the socket has been placed in non-blocking I/O
mode. In non-blocking mode it would return
EAGAIN
in this case.
The
select (2)
call may be used to determine when it is possible to send more data.
The
flags
parameter is a flagword and can contain the following flags:
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