getsockopt(3XNET)X/Open Networking Services Library Functionsgetsockopt(3XNET)NAMEgetsockopt - get the socket options
SYNOPSIS
cc [ flag... ] file... -lxnet [ library... ]
#include <sys/socket.h>
int getsockopt(int socket, int level, int option_name,
void *restrict option_value, socklen_t *restrict option_len);
DESCRIPTION
The getsockopt() function retrieves the value for the option specified
by the option_name argument for the socket specified by the socket
argument. If the size of the option value is greater than option_len,
the value stored in the object pointed to by the option_value argument
will be silently truncated. Otherwise, the object pointed to by the
option_len argument will be modified to indicate the actual length of
the value.
The level argument specifies the protocol level at which the option
resides. To retrieve options at the socket level, specify the level
argument as SOL_SOCKET. To retrieve options at other levels, supply the
appropriate protocol number for the protocol controlling the option.
For example, to indicate that an option will be interpreted by the TCP
(Transport Control Protocol), set level to the protocol number of TCP,
as defined in the <netinet/in.h> header, or as determined by using get‐
protobyname(3XNET) function.
The socket in use might require the process to have appropriate privi‐
leges to use the getsockopt() function.
The option_name argument specifies a single option to be retrieved. It
can be one of the following values defined in <sys/socket.h>:
SO_DEBUG Reports whether debugging information is being
recorded. This option stores an int value. This is a
boolean option.
SO_ACCEPTCONN Reports whether socket listening is enabled. This
option stores an int value.
SO_BROADCAST Reports whether transmission of broadcast messages is
supported, if this is supported by the protocol. This
option stores an int value. This is a boolean option.
SO_REUSEADDR Reports whether the rules used in validating addresses
supplied to bind(3XNET) should allow reuse of local
addresses, if this is supported by the protocol. This
option stores an int value. This is a boolean option.
SO_KEEPALIVE Reports whether connections are kept active with peri‐
odic transmission of messages, if this is supported by
the protocol.
If the connected socket fails to respond to these mes‐
sages, the connection is broken and threads writing to
that socket are notified with a SIGPIPE signal. This
option stores an int value.
This is a boolean option.
SO_LINGER Reports whether the socket lingers on close(2) if data
is present. If SO_LINGER is set, the system blocks the
process during close(2) until it can transmit the data
or until the end of the interval indicated by the
l_linger member, whichever comes first. If SO_LINGER
is not specified, and close(2) is issued, the system
handles the call in a way that allows the process to
continue as quickly as possible. This option stores a
linger structure.
SO_OOBINLINE Reports whether the socket leaves received out-of-band
data (data marked urgent) in line. This option stores
an int value. This is a boolean option.
SO_SNDBUF Reports send buffer size information. This option
stores an int value.
SO_RCVBUF Reports receive buffer size information. This option
stores an int value.
SO_ERROR Reports information about error status and clears it.
This option stores an int value.
SO_TYPE Reports the socket type. This option stores an int
value.
SO_DONTROUTE Reports whether outgoing messages bypass the standard
routing facilities. The destination must be on a
directly-connected network, and messages are directed
to the appropriate network interface according to the
destination address. The effect, if any, of this
option depends on what protocol is in use. This option
stores an int value. This is a boolean option.
SO_MAC_EXEMPT Gets the mandatory access control status of the
socket. A socket that has this option enabled can com‐
municate with an unlabeled peer if the socket is in
the global zone or has a label that dominates the
default label of the peer. Otherwise, the socket must
have a label that is equal to the default label of the
unlabeled peer. SO_MAC_EXEMPT is a boolean option that
is available only when the system is configured with
Trusted Extensions.
SO_ALLZONES Bypasses zone boundaries (privileged). This option
stores an int value. This is a boolean option.
The SO_ALLZONES option can be used to bypass zone
boundaries between shared-IP zones. Normally, the sys‐
tem prevents a socket from being bound to an address
that is not assigned to the current zone. It also pre‐
vents a socket that is bound to a wildcard address
from receiving traffic for other zones. However, some
daemons which run in the global zone might need to
send and receive traffic using addresses that belong
to other shared-IP zones. If set before a socket is
bound, SO_ALLZONES causes the socket to ignore zone
boundaries between shared-IP zones and permits the
socket to be bound to any address assigned to the
shared-IP zones. If the socket is bound to a wildcard
address, it receives traffic intended for all shared-
IP zones and behaves as if an equivalent socket were
bound in each active shared-IP zone. Applications that
use the SO_ALLZONES option to initiate connections or
send datagram traffic should specify the source
address for outbound traffic by binding to a specific
address. There is no effect from setting this option
in an exclusive-IP zone. Setting this option requires
the sys_net_config privilege. See zones(5).
SO_DOMAIN get the domain used in the socket (get only)
SO_PROTOTYPE for socket in domains AF_INET and AF_INET6, get the
underlying protocol number used in the socket. For
socket in domain AF_ROUTE, get the address family used
in the socket.
For boolean options, a zero value indicates that the option is disabled
and a non-zero value indicates that the option is enabled.
Options at other protocol levels vary in format and name.
The socket in use may require the process to have appropriate privi‐
leges to use the getsockopt() function.
RETURN VALUES
Upon successful completion, getsockopt() returns 0. Otherwise, −1 is
returned and errno is set to indicate the error.
ERRORS
The getsockopt() function will fail if:
EBADF The socket argument is not a valid file descriptor.
EFAULT The option_value or option_len parameter can not be
accessed or written.
EINVAL The specified option is invalid at the specified socket
level.
ENOPROTOOPT The option is not supported by the protocol.
ENOTSOCK The socket argument does not refer to a socket.
The getsockopt() function may fail if:
EACCES The calling process does not have the appropriate privi‐
leges.
EINVAL The socket has been shut down.
ENOBUFS Insufficient resources are available in the system to com‐
plete the call.
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 │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
├─────────────────────────────┼─────────────────────────────┤
│Standard │See standards(5). │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOclose(2), bind(3XNET), endprotoent(3XNET), setsockopt(3XNET),
socket(3XNET), attributes, standards(5)SunOS 5.11 21 Jan 2007 getsockopt(3XNET)