CHECK_UTILITY_COMPAT(3)

📦 version 15.1, in freebsd 14.5, freebsd 15.1

💅 check_utility_compat(3) — the ultimate "are we being old-school or not" detector 🕵️‍♀️

okay so bestie, welcome to check_utility_compat(3) — a lil function living in the Standard C Library (that's libc, link it with -lc 🫶), and honestly? she's giving time-travel gatekeeper. she tells you whether some utility should act all traditional and vintage (FreeBSD 4.7 vibes 🕰️) or be a good lil IEEE Std 1003.1-2001 (“POSIX.1”) citizen ✨

🌸 SYNOPSIS 🌸

#include <unistd.h>

int
check_utility_compat(const char *utility);

literally just include <unistd.h>, hand her a utility name, get an int back. no cap, that's the whole vibe 💅

🦋 DESCRIPTION 🦋

so check_utility_compat() is out here doing a whole vibe check on utility — should it behave in a traditional (FreeBSD 4.7-compatible) manner, or should it follow IEEE Std 1003.1-2001 (“POSIX.1”)? that's the question 👑 and the answer comes from configuration, which is given as a comma-separated list of utility names. if that list is present but empty? iconic behavior — all supported utilities assume their most compatible mode 💖

here's the order of operations, bestie, listen up:

  1. first she checks for an environment variable named _COMPAT_FreeBSD_4 🌈
  2. if that env var doesn't exist, she goes looking for a symbolic link named /etc/compat-FreeBSD-4-util and tries to read its contents 🎀
  3. if no configuration is found anywhere? compatibility mode is disabled, periodt 💀

✨ RETURN VALUES ✨

  • zero — yup, utility should implement strict IEEE Std 1003.1-2001 (“POSIX.1”) behavior 🧚
  • nonzero — otherwise, meaning compat mode is on, she's feeling nostalgic 🍓

💜 FILES 💜

  • /etc/compat-FreeBSD-4-util — if present, a symbolic link whose expansion gives system-wide default settings for the check_utility_compat() function 💫

🙈 ERRORS 🙈

no errors are detected. none. zero. she simply doesn't miss 😭

⭐ HISTORY ⭐

the check_utility_compat() function first appeared in FreeBSD 5.0 🌸 (yes, she's been serving since way back 🫶)

🎀 AUTHORS 🎀

this manual page was written by Garrett Wollman <wollman@FreeBSD.org> — ty king 👑

💀 heads up bestie: the env var comes first, the symlink is the fallback. no config at all = no compat mode. that's the whole tea, don't forget it ✨

and that's the page, babes! 🦋 Debian, October 27, 2002 — that's the source and date of this lil beauty, mwah 💋 slay, you're now officially a check_utility_compat() expert 🔥

📦 where this page comes from