svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
sendto(3c)
send(3C) Standard C Library Functions send(3C)
NAME
send, sendto, sendmsg - send a message from a socket
SYNOPSIS
#include <sys/socket.h>
ssize_t send(int s, const void *msg, size_t len, int flags);
ssize_t sendto(int s, const void *msg, size_t len, int flags,
const struct sockaddr *to, socklen_t tolen);
ssize_t sendmsg(int s, const struct msghdr *msg, int flags);
DESCRIPTION
The send(), sendto(), and sendmsg() functions are used to transmit a
message to another transport end-point. The send() function can be used
only when the socket is in a connected state. See connect(3C). The
sendto() and sendmsg() functions can be used at any time. The s socket
is created with socket(3C).
The address of the target is supplied by to with a tolen parameter used
to specify the size. The length of the message is supplied by the len
parameter. For socket types such as SOCK_DGRAM and SOCK_RAW that re‐
quire atomic messages, the error EMSGSIZE is returned and the message
is not transmitted when it is too long to pass atomically through the
underlying protocol. The same restrictions do not apply to SOCK_STREAM
sockets.
A return value −1 indicates locally detected errors. It does not imply
a delivery failure.
If the socket does not have enough buffer space available to hold a
message, the send() function blocks the message, unless the socket has
been placed in non-blocking I/O mode (see fcntl(2)). The select(3C) or
poll(2) call can be used to determine when it is possible to send more
data.
The flags parameter is formed from the bitwise OR of zero or more of
the following:
MSG_OOB Send out-of-band data on sockets that support this no‐
tion. The underlying protocol must also support out-
of-band data. Only SOCK_STREAM sockets created in the
AF_INET or the AF_INET6 address family support out-of-
band data.
MSG_DONTROUTE The SO_DONTROUTE option is turned on for the duration
of the operation. It is used only by diagnostic or
routing programs.
MSG_NOSIGNAL The MSG_NOSIGNAL flag requests not to send the SIGPIPE
signal if an attempt to send is made on a stream-ori‐
ented socket that is no longer connected. The EPIPE
error is still returned.
The sendmsg() function call uses a msghdr structure defined in
socket.h(3HEAD) to minimize the number of directly supplied parameters.
sendmmsg(3C) is an extension of the sendmsg() function that allows re‐
ceiving multiple messages in a single call.
The contents of the msghdr structure differ depending on whether or not
__USE_SUNOS_SOCKETS__ is defined before including the <sys/socket.h>
header. All source files accessing msghdr structures or calling the
sendmsg() function must be compiled with either __USE_SUNOS_SOCKETS__
defined or all with it undefined — mixing and matching will not work.
See the socket.h(3HEAD) manual page for details.
RETURN VALUES
Upon successful completion, these functions return the number of bytes
sent. Otherwise, they return -1 and set errno to indicate the error.
ERRORS
The send(), sendto(), and sendmsg() functions return errors under the
following conditions:
EBADF s is not a valid file descriptor.
EINTR The operation was interrupted by delivery of a signal
before any data could be buffered to be sent.
EMSGSIZE The message is too large to be sent all at once (as the
socket requires), or the msg_iovlen member of the ms‐
ghdr structure pointed to by message is less than or
equal to 0 or is greater than {IOV_MAX}.
ENOMEM Insufficient memory is available to complete the opera‐
tion.
ENOSR Insufficient STREAMS resources are available for the
operation to complete.
ENOTSOCK s is not a socket.
EWOULDBLOCK The socket is marked non-blocking and the requested op‐
eration would block. EWOULDBLOCK is also returned when
sufficient memory is not immediately available to allo‐
cate a suitable buffer. In such a case, the operation
can be retried later. Another reason is if the socket
option SO_SNDTIMEO has been set and the requested oper‐
ation fails to transfer data before the timeout ex‐
pired. For more information, see the getsockopt(3C) man
page.
ECONNREFUSED The requested connection was refused by the peer. For
connected IPv4 and IPv6 datagram sockets, this indi‐
cates that the system received an ICMP Destination Port
Unreachable message from the peer in response to some
prior transmission.
The send() and sendto() functions return errors under the following
conditions:
EFAULT buf points to an illegal address.
EINVAL The len argument overflows a ssize_t.
Inconsistent port attributes for system call.
The sendto() function returns errors under the following conditions:
EINVAL The value specified for the tolen parameter is not the size
of a valid address for the specified address family.
EISCONN A destination address was specified and the socket is al‐
ready connected.
The sendmsg() function returns errors under the following conditions:
EFAULT msg points to an illegal address.
EINVAL The msg_iovlen member of the msghdr structure pointed to by
msg is less than or equal to 0, or the sum of the iov_len
values in the msg_iov array overflows a ssize_t.
One of the iov_len values in the msg_iov array member of the
msghdr structure pointed to by msg is negative, or the sum of
the iov_len values in the msg_iov array overflows a ssize_t.
msg_iov contents are inconsistent with port attributes.
The send() function returns errors under the following conditions:
EPIPE The socket is shut down for writing, or the socket is connec‐
tion-mode and is no longer connected. In the latter case, if
the socket is of type SOCK_STREAM, the SIGPIPE signal is gen‐
erated to the calling thread unless MSG_NOSIGNAL is set.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
TRIBUTE VALUE _ Interface StabilityCommitted _ MT-LevelAsync-Signal-
Safe _ StandardSee standards(7).
SEE ALSO
fcntl(2), poll(2), write(2), connect(3C), getsockopt(3C), recv(3C), se‐
lect(3C), sendmmsg(3C), socket(3C), socket.h(3HEAD), attributes(7)
HISTORY
These functions have been present since the initial release of Solaris.
Oracle Solaris 11.4 2 Feb 2021 send(3C)