Signed-off-by: Alejandro Colomar <alx@kernel.org>
The socket option level for IP is
.BR IPPROTO_IP .
.\" or SOL_IP on Linux
-A boolean integer flag is zero when it is false, otherwise true.
.P
-When an invalid socket option is specified,
-.BR getsockopt (2)
-and
-.BR setsockopt (2)
-fail with the error
-.BR ENOPROTOOPT .
+The following socket options are supported.
.TP
.BR IP_ADD_MEMBERSHIP (2const)
.TQ
.BR setsockopt (2).
See
.BR ip (7).
+.TP
+.B ENOPROTOOPT
+.I opt
+is invalid.
.\" .SH STANDARDS
.\" IP_XFRM_POLICY is Linux-specific
.\" IP_IPSEC_POLICY is a nonstandard extension, also present on some BSDs