getsockopt(3XNET)				   X/Open Networking Services Library Functions 				 getsockopt(3XNET)

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  argu-
       ment  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.

       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(5) 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(5)

SunOS 5.10							    10 Dec 2003 						 getsockopt(3XNET)