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

NAME

       setsockopt - set the socket options

SYNOPSIS

       cc [ flag... ] file... -lxnet [ library... ]
       #include <sys/socket.h>

       int setsockopt(int socket, int level, int option_name, const void*option_value, socklen_t option_len);

DESCRIPTION

       The  setsockopt() function sets the option specified by the option_name argument, at the protocol level specified by the level argument, to
       the value pointed to by the option_value argument for the socket associated with the file descriptor specified by the socket argument.

       The level argument specifies the protocol level at which the option resides.  To set options at the socket level, specify the  level  argu-
       ment  as  SOL_SOCKET.  To set 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).

       The  option_name argument specifies a single option to set.  The option_name argument and any specified options are passed uninterpreted to
       the appropriate protocol module for interpretations.  The <sys/socket.h> header defines the socket level options.  The options are as  fol-
       low

       SO_DEBUG 	       Turns  on recording of debugging information.  This option enables or disables debugging in the underlying protocol
			       modules.  This option takes an int value. This is a boolean option.

       SO_BROADCAST	       Permits sending of broadcast messages, if this is supported by the protocol. This option takes an int  value.  This
			       is a boolean option.

       SO_REUSEADDR	       Specifies  that	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 takes an int value. This is a boolean option.

       SO_KEEPALIVE	       Keeps connections active by enabling the periodic transmission of messages, if this is supported by  the  protocol.
			       This option takes an int value.

			       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 is a boolean option.

       SO_LINGER	       Lingers on a close(2) if data is present.  This option controls the action taken when unsent messages  queue  on  a
			       socket  and close(2) is performed.  If SO_LINGER is set, the system blocks the process during close(2) until it can
			       transmit the data or until the time expires.  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 takes a linger
			       structure, as defined in the <sys/socket.h> header, to specify the state of the option and linger interval.

       SO_OOBINLINE	       Leaves received out-of-band data (data marked urgent) in line. This option takes an int value. This  is	a  boolean
			       option.

       SO_SNDBUF	       Sets send buffer size.  This option takes an  int value.

       SO_RCVBUF	       Sets receive buffer size.  This option takes an	int value.

       SO_DONTROUTE	       Requests  that outgoing messages bypass the standard routing facilities. The destination must be on a directly-con-
			       nected  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 takes an	int value.
			       This is a boolean option.

       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.

USAGE

       The setsockopt() function provides an application program with the means to control socket behavior.  An application program can  use  set-
       sockopt() to allocate buffer space, control timeouts, or permit socket data broadcasts.	The <sys/socket.h> header defines the socket-level
       options available to setsockopt().

       Options may exist at multiple protocol levels. The SO_ options are always present at the uppermost socket level.

RETURN VALUES

       Upon successful completion, setsockopt() returns 0.  Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The setsockopt() function will fail if:

       EBADF		       The socket argument is not a valid file descriptor.

       EDOM		       The send and receive timeout values are too big to fit into the timeout fields in the socket structure.

       EFAULT		       The  option_value parameter can not be accessed or written.

       EINVAL		       The specified option is invalid at the specified socket level or the socket has been shut down.

       EISCONN		       The socket is already connected, and a  specified option can not be set while the socket is connected.

       ENOPROTOOPT	       The option is not supported by the protocol.

       ENOTSOCK 	       The socket argument does not refer to a socket.

       The setsockopt() function may fail if:

       ENOMEM		       There was insufficient memory available for the operation to complete.

       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

       bind(3XNET), endprotoent(3XNET), getsockopt(3XNET), socket(3XNET), attributes(5), standards(5)

SunOS 5.10							    1 Nov 2003							 setsockopt(3XNET)