.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
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.TH IPV6_UNICAST_HOPS 2const 2026-01-05 "Linux man-pages 6.17"
.SH NAME
IPV6_UNICAST_HOPS
\-
unicast hop limit
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <netinet/in.h>" "  /* Definition of " IP* " constants */"
.B #include <sys/socket.h>
.P
.BI int\~setsockopt(int\~ sockfd ,\~IPPROTO_IPV6,\~IPV6_UNICAST_HOPS,
.BI "               const\~int\~*" hops ,\~sizeof(int));
.fi
.SH DESCRIPTION
Set the unicast hop limit for the socket.
.P
A value of
.B \-1
means use the route default;
otherwise it should be in the range
.RB [ 0 ,
.BR 255 ].
.SH ERRORS
See
.BR IPPROTO_IPV6 (2const).
See
.BR setsockopt (2).
See
.BR ipv6 (7).
.SH HISTORY
.TP
.B IPV6_UNICAST_HOPS
POSIX.1-2001.
.SH SEE ALSO
.BR IPPROTO_IPV6 (2const),
.BR setsockopt (2),
.BR ipv6 (7)