getsockopt(3N-xs)             (X/OPEN SOCKETS)            getsockopt(3N-xs)

NAME
     getsockopt - get the socket options

SYNOPSIS
     cc [flag ...] file ... -lxnet [library ...]

     #include <sys/socket.h>

     int getsockopt(int socket, int level, int optionname,
                    void *optionvalue, sizet *optionlen);

DESCRIPTION
     The getsockopt function retrieves the value for the option specified
     by the optionname argument for the socket specified by the socket
     argument. If the size of the option value is greater than optionlen,
     the value stored in the object pointed to by the optionvalue argument
     will be silently truncated. Otherwise, the object pointed to by the
     optionlen 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 SOLSOCKET. 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 function.

     The optionname argument specifies a single option to be retrieved. It
     can be one of the following values defined in <sys/socket.h>:

     SODEBUG            Reports whether debugging information is being
                         recorded. This option stores an int value.

     SOACCEPTCONN       Reports whether socket listening is enabled. This
                         option stores an int value.

     SOBROADCAST        Reports whether transmission of broadcast messages
                         is supported, if this is supported by the proto-
                         col. This option stores an int value.

     SOREUSEADDR        Reports whether the rules used in validating
                         addresses supplied to bind should allow reuse of
                         local addresses, if this is supported by the pro-
                         tocol. This option stores an int value.









Page 1                       Reliant UNIX 5.44                Printed 11/98

getsockopt(3N-xs)             (X/OPEN SOCKETS)            getsockopt(3N-xs)

     SOKEEPALIVE        Reports whether connections are kept active with
                         periodic transmission of messages, if this is sup-
                         ported by the protocol.

                         If the connected socket fails to respond to these
                         messages, the connection is broken and processes
                         writing to that socket are notified with a SIGPIPE
                         signal. This option stores an int value.

     SOLINGER           Reports whether the socket lingers on close if
                         data is present. If SOLINGER is set, the system
                         blocks the process during close until it can
                         transmit the data or until the end of the interval
                         indicated by the llinger member, whichever comes
                         first. If SOLINGER is not specified, and close is
                         issued, the system handles the call in a way that
                         allows the process to continue as quickly as pos-
                         sible. This option stores a linger structure.

     SOOOBINLINE        Reports whether the socket leaves received out-
                         of-band data (data marked urgent) in line. This
                         option stores an int value.

     SOSNDBUF           Reports send buffer size information. This option
                         stores an int value.

     SORCVBUF           Reports receive buffer size information. This
                         option stores an int value.

     SOERROR            Reports information about error status and clears
                         it. This option stores an int value.

     SOTYPE             Reports the socket type. This option stores an int
                         value. For boolean options, 0 indicates that the
                         option is disabled and 1 indicates that the option
                         is enabled. Options at other protocol levels vary
                         in format and name.

RETURN VALUE
     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 descrip-
                         tor.

     ENOPROTOOPT         The option is not supported by the protocol.

     ENOTSOCK            The socket argument does not refer to a socket.



Page 2                       Reliant UNIX 5.44                Printed 11/98

getsockopt(3N-xs)             (X/OPEN SOCKETS)            getsockopt(3N-xs)

     EINVAL              The specified option is invalid at the specified
                         socket level.

     EOPNOTSUPP          The operation is not supported by the socket pro-
                         tocol.

     The getsockopt function may fail if:

     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 avail-
                         able for the operation to complete.

SEE ALSO
     close(2), bind(3N-xs), getprotoent(3N-xs), getsockopt(3N-xs),
     socket(3N-xs), ip(7).



































Page 3                       Reliant UNIX 5.44                Printed 11/98