.Fa "socklen_t option_len"
.Fc
.Sh DESCRIPTION
-.Fn Getsockopt
+.Fn getsockopt
and
.Fn setsockopt
manipulate the
.It Dv SO_TYPE Ta "get the type of the socket (get only)"
.It Dv SO_ERROR Ta "get and clear error on the socket (get only)"
.It Dv SO_NOSIGPIPE Ta "do not generate SIGPIPE, instead return EPIPE"
+.It Dv SO_NREAD Ta "number of bytes to be read (get only)"
+.It Dv SO_NWRITE Ta "number of bytes written not yet sent by the protocol (get only)"
+.It Dv SO_LINGER_SEC Ta "linger on close if data present with timeout in seconds"
.El
.Pp
.Dv SO_DEBUG
enables debugging in the underlying protocol modules.
+.Pp
.Dv SO_REUSEADDR
indicates that the rules used in validating addresses supplied
in a
.Xr bind 2
call should allow reuse of local addresses.
+.Pp
.Dv SO_REUSEPORT
allows completely duplicate bindings by multiple processes
if they all set
before binding the port.
This option permits multiple instances of a program to each
receive UDP/IP multicast or broadcast datagrams destined for the bound port.
+.Pp
.Dv SO_KEEPALIVE
enables the
periodic transmission of messages on a connected socket. Should the
considered broken and processes using the socket are notified via a
.Dv SIGPIPE
signal when attempting to send data.
+.Pp
.Dv SO_DONTROUTE
indicates that outgoing messages should
bypass the standard routing facilities. Instead, messages are directed
is issued, the system will process the close in a manner that allows
the process to continue as quickly as possible.
.Pp
+.Dv SO_LINGER_SEC
+is the same option as
+.Dv SO_LINGER
+except the linger time is in seconds for
+.Dv SO_LINGER_SEC .
+.Pp
The option
.Dv SO_BROADCAST
requests permission to send broadcast datagrams
on the socket.
Broadcast was a privileged operation in earlier versions of the system.
+.Pp
With protocols that support out-of-band data, the
.Dv SO_OOBINLINE
option
.Dv MSG_OOB
flag.
Some protocols always behave as if this option is set.
+.Pp
.Dv SO_SNDBUF
and
.Dv SO_RCVBUF
only if the low-water mark amount could be processed.
The default value for
.Dv SO_SNDLOWAT
-is set to a convenient size for network efficiency, often 1024.
+is set to a convenient size for network efficiency, often 2048.
.Pp
.Dv SO_RCVLOWAT
is an option to set the minimum count for input operations.
when there is no reader.
.Pp
Finally,
-.Dv SO_TYPE
-and
-.Dv SO_ERROR
+.Dv SO_TYPE ,
+.Dv SO_ERROR ,
+.Dv SO_NREAD , and
+.Dv SO_NWRITE
are options used only with
.Fn getsockopt .
+.Pp
.Dv SO_TYPE
returns the type of the socket, such as
.Dv SOCK_STREAM ;
it is useful for servers that inherit sockets on startup.
+.Pp
.Dv SO_ERROR
returns any pending error on the socket and clears
the error status.
It may be used to check for asynchronous errors on connected
datagram sockets or for other asynchronous errors.
+.Pp
+.Dv SO_NREAD
+returns the amount of data in the input buffer that is available to be received.
+For datagram oriented sockets,
+.Dv SO_NREAD
+returns the size of the first packet -- this differs from the
+.Fn ioctl
+command
+.Dv FIONREAD
+that returns the total amount of data available.
+.Pp
+.Dv SO_NWRITE
+returns the amount of data in the output buffer not yet sent by the protocol.
.Sh RETURN VALUES
.Rv -std
.Sh ERRORS
The option is invalid at the level indicated.
.\" ==========
.It Bq Er ENOBUFS
-Insufficient memory buffers are available.
+Insufficient system resources available for the call to complete.
+.\" ==========
+.It Bq Er ENOMEM
+Insufficient memory available for the system call to complete.
.\" ==========
.It Bq Er ENOPROTOOPT
The option is unknown at the level indicated.
is already connected
and a specified option cannot be set
while this is the case.
+.\" ==========
+.It Bq Er EINVAL
+The socket has been shut down.
.El
.Sh LEGACY SYNOPSIS
.Fd #include <sys/types.h>
.In sys/types.h
is necessary.
.Sh SEE ALSO
-.Xr ioctl 2 ,
.Xr socket 2 ,
+.Xr bind 2 ,
+.Xr ioctl 2 ,
.Xr getprotoent 3 ,
.Xr protocols 5
.Sh BUGS