IFNAMES(1)

✨ NAME ✨

ifnames — ok so bestie, this little icon extracts CPP conditionals from a whole set of files 💖 it's giving "who even asked for this preprocessor flag" energy

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🌸 SYNOPSIS 🌸

ifnames [OPTION]... [FILE]...

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💅 DESCRIPTION 💅

So here's the vibe: ifnames scans all of the C source FILES — or, if you don't hand it any, it reads the standard input, no big deal — and then it writes to the standard output a sorted list of every single identifier that shows up in those files inside #if, #ifdef, #ifndef, #elif, #elifdef, or #elifndef directives. Obsessed, honestly.

It prints each identifier on its own line, followed by a space-separated list of the files where that identifier occurs. Like, receipts. Every single one. 🧾

• -h, --help — prints this help, then dips out (exits) 🫶
• -V, --version — prints the version number, then dips out (exits) 👑

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🎀 AUTHOR 🎀

Written by David J. MacKenzie and Paul Eggert. Legends, fr fr. 👑

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🦋 REPORTING BUGS 🦋

Found a bug? Not the vibe. Report it to bug-autoconf@gnu.org, or slide into Savannah instead: https://savannah.gnu.org/support/?group=autoconf. They wanna hear it, no cap. 🙈

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💖 COPYRIGHT 💖

Copyright © 2026 Free Software Foundation, Inc. License: GPLv3+/Autoconf: GNU GPL version 3 or later https://gnu.org/licenses/gpl.html, https://gnu.org/licenses/exceptions.html

This is free software: you are free to change it and redistribute it. And there is NO WARRANTY, to the extent permitted by law. Like, none. Zero. Don't come for them if it goes sideways. 💀

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🌈 SEE ALSO 🌈

• autoconf(1), automake(1), autoreconf(1), autoupdate(1), autoheader(1), autoscan(1), config.guess(1), config.sub(1), ifnames(1), libtool(1)

The full documentation for Autoconf is maintained as a Texinfo manual (iykyk). To read the manual locally, use this command:

info autoconf

You can also consult the Web version of the manual at https://gnu.org/software/autoconf/manual/. Go off. 📖✨

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Ok that's the whole thing, bestie — this page is GNU Autoconf 2.73, from March 2026, and it's the IFNAMES(1) page. Slay, bye! 💅💖