mirror of https://github.com/mkerrisk/man-pages
106 lines
2.7 KiB
Groff
106 lines
2.7 KiB
Groff
.\" Copyright (c) 2012 YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
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.\"
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.\" %%%LICENSE_START(VERBATIM)
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of
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.\" this manual under the conditions for verbatim copying, provided that
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.\" the entire resulting derived work is distributed under the terms of
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.\" a permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume
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.\" no responsibility for errors or omissions, or for damages resulting
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.\" from the use of the information contained herein. The author(s) may
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.\" not have taken the same level of care in the production of this
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.\" manual, which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\" %%%LICENSE_END
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.\"
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.TH IF_NAMETOINDEX 3 2015-03-02 "GNU" "Linux Programmer's Manual"
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.SH NAME
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if_nametoindex, if_indextoname \- mappings between network interface
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names and indexes
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.SH SYNOPSIS
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.nf
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.B #include <net/if.h>
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.sp
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.BI "unsigned int if_nametoindex(const char *" "ifname" );
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.sp
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.BI "char *if_indextoname(unsigned int ifindex, char *" ifname );
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.fi
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.SH DESCRIPTION
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The
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.BR if_nametoindex ()
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function returns the index of the network interface
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corresponding to the name
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.IR ifname .
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The
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.BR if_indextoname ()
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function returns the name of the network interface
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corresponding to the interface index
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.IR ifindex .
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The name is placed in the buffer pointed to by
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.IR ifname .
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The buffer must allow for the storage of at least
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.B IF_NAMESIZE
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bytes.
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.SH RETURN VALUE
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On success,
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.BR if_nametoindex ()
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returns the index number of the network interface;
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on error, 0 is returned and
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.I errno
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is set appropriately.
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On success,
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.BR if_indextoname ()
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returns
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.IR ifname ;
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on error, NULL is returned and
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.I errno
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is set appropriately.
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.SH ERRORS
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.BR if_indextoname ()
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may fail and set
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.I errno
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if:
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.TP
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.B ENXIO
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No interface found for the index.
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.PP
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.BR if_nametoindex ()
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and
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.BR if_indextoname ()
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may also fail for any of the errors specified for
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.BR socket (2)
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or
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.BR ioctl (2).
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.SH ATTRIBUTES
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For an explanation of the terms used in this section, see
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.BR attributes (7).
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.TS
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allbox;
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lbw34 lb lb
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l l l.
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Interface Attribute Value
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T{
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.BR if_nametoindex (),
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.BR if_indextoname ()
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T} Thread safety MT-Safe
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.TE
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.SH CONFORMING TO
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RFC\ 3493, POSIX.1-2001.
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This function first appeared in BSDi.
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.SH SEE ALSO
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.BR getifaddrs (3),
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.BR if_nameindex (3),
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.BR ifconfig (8)
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