TIOCCONS(2const)

✨ NAME ✨

TIOCCONS — redirecting console output 💖 (it's a 2const page bestie, we love a const)

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📚 LIBRARY

Standard C library (libc, -lc) 🫶

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🌸 SYNOPSIS

#include <asm/termbits.h>  /* Definition of TIOCCONS */
#include <sys/ioctl.h>

int ioctl(int fd, TIOCCONS);

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👑 DESCRIPTION

Okay so picture this: output is out here living its life, headed straight for /dev/console or /dev/tty0, and you're like "no babe, wrong direction." That's what this does — it redirects output that would have gone to /dev/console or /dev/tty0 to the given terminal. And if that terminal was a pseudoterminal master? Then the output gets sent to the slave instead. Slay. ✨

But here's the gatekeeping part: only a process with the CAP_SYS_ADMIN capability may do this. No cap, no redirect. 💅

And if output was redirected already, then EBUSY is returned. BUT — plot twist — redirection can be stopped by using this ioctl with fd pointing at /dev/console or /dev/tty0. So you're not stuck, bestie, there's a way out. 🦋

⚠️ Lowkey important: remember that CAP_SYS_ADMIN requirement, because it was NOT always a thing. Keep reading. 👀

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🎀 RETURN VALUE

On success, 0 is returned. Iconic, perfect, no notes. 🌟

On error, -1 is returned, and errno is set to indicate the error. Rude, but informative. 😭

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💀 ERRORS

• EBUSY — Output was redirected already. Somebody got there first, the console is taken, it's giving occupied. 🚫
• EPERM — Insufficient permission. You simply do not have the CAP_SYS_ADMIN pass. Not you, bestie. 🙈

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🕰️ HISTORY

Before Linux 2.6.10, anybody can do this as long as the output was not redirected yet; CAP_SYS_ADMIN was not necessary. Wild times. The old days were lawless fr fr. 💀✨

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🔗 SEE ALSO

• ioctl(2)
• ioctl_tty(2)

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And that's the whole page, bestie — go redirect some console output responsibly. This was TIOCCONS(2const) from Linux man-pages 6.20, dated 2026-02-08. Mwah, ily, go read ioctl_tty(2) next. 💖🎀🦋