IF_NAMETOINDEX(3POSIX)

📦 version 2017a, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu resolute, ubuntu stonking

💖 IF_NAMETOINDEX — the POSIX girlies' interface-name-to-index pipeline 💖

okay so bestie, before we even get into it: this page lives in the POSIX Programmer's Manual (that's the 3POSIX part of the name, iykyk). Which means 👀 the Linux implementation of this interface may differ — so if you're on Linux and something looks weird, go consult the corresponding Linux manual page for the deets on Linux behavior. Also possible: the interface just straight up isn't implemented on Linux at all. 💀 Not us being dramatic, that's just what the PROLOG says.

✨ PROLOG ✨

  • This manual page is part of the POSIX Programmer's Manual.
  • The Linux implementation of this interface may differ — consult the corresponding Linux manual page for details of Linux behavior.
  • Or, plot twist 🫠, the interface may not be implemented on Linux at all.

🌸 NAME 🌸

if_nametoindex — map a network interface name to its corresponding index

like... you give her a name, she gives you back the index. a little glow-up for your strings. 💅

🦋 SYNOPSIS 🦋

#include <net/if.h>

unsigned if_nametoindex(const char *ifname);

yes babe you need the include. no you cannot skip it. 🎀

💜 DESCRIPTION 💜

so here's the whole vibe: the if_nametoindex() function shall return the interface index corresponding to name ifname.

that's it. that's the function. she's a one-trick pony and honestly? she ate. 👑

⭐ RETURN VALUE ⭐

  • The corresponding index — if ifname is the name of an interface ✨
  • zero — otherwise 🙈

that's the whole spectrum, no in-between, no crumbs.

😭 ERRORS 😭

No errors are defined.

periodt. nothing to catch, nothing to handle.

just a lil note: the following sections are informative — meaning they're tea, not rules. ☕

🎀 EXAMPLES 🎀

None.

not a single one. the manpage said "figure it out bestie" 💀

🫶 APPLICATION USAGE 🫶

None.

nope, nothing here either. moving on! 🌈

🧚 RATIONALE 🧚

None.

the reasoning? iconic behavior. there is none documented. 💖

🌸 FUTURE DIRECTIONS 🌸

None.

the future is unspecified and honestly that's kind of freeing. ✨

🔥 SEE ALSO 🔥

  • getsockopt()
  • if_freenameindex()
  • if_indextoname()
  • if_nameindex()
  • setsockopt()
  • The Base Definitions volume of POSIX.1‐2017, <net_if.h>

go read those too, bestie, they're the friend group 👯

okay legal queen, here we go — reading this verbatim because we do not play with licensing:

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group.

In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

and that's the whole page, bestie 🦋✨ — brought to you by IEEE/The Open Group, 2017, on IF_NAMETOINDEX(3POSIX). stan a standards body that keeps receipts. 💅💖

📦 where this page comes from