.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH IP_RECVTTL 2const (date) "Linux man-pages (unreleased)"
.SH NAME
IP_RECVTTL
\-
enable IP_TTL control message
.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_IP,\~int\~ opt ,
.BI "               const\~int\~*" enable ,\~sizeof(int));
.fi
.SH DESCRIPTION
When this flag is set,
pass a
.BR IP_TTL (2const)
control message
with the time-to-live field
of the received packet as a 32 bit integer.
.P
Not supported for
.B SOCK_STREAM
sockets.
.SH ERRORS
See
.BR IPPROTO_IP (2const).
See
.BR setsockopt (2).
See
.BR ip (7).
.SH VERSIONS
Some BSD sockets implementations also provide an
.B IP_RECVTTL
option, but an ancillary message with type
.B IP_RECVTTL
is passed with the incoming packet.
This is different from the
.BR IP_TTL (2const)
option used in Linux.
.SH HISTORY
Linux 2.2.
.\" Precisely: since Linux 2.1.68
.SH SEE ALSO
.BR IPPROTO_IP (2const),
.BR setsockopt (2),
.BR ip (7)