GETSOCKOPT(3XNET) X/Open Networking Services Library Functions
NAME
getsockopt - 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
getprotobyname(3XNET) function.
The socket in use might require the process to have appropriate
privileges 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
periodic transmission of messages, if this is supported
by the protocol.
If the connected socket fails to respond to these
messages, 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 communicate
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 system
prevents a socket from being bound to an address that is
not assigned to the current zone. It also prevents 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(7).
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 privileges
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 privileges.
EINVAL The socket has been shut down.
ENOBUFS Insufficient resources are available in the system to complete
the call.
ENOSR There were insufficient STREAMS resources available for the
operation to complete.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+
SEE ALSO
close(2),
bind(3XNET),
endprotoent(3XNET),
setsockopt(3XNET),
socket(3XNET),
attributes,
standards(7) January 21, 2007
GETSOCKOPT(3XNET)