TIOCCONS(2const) TIOCCONS(2const)

TIOCCONS - redirecting console output

Standard C library (libc, -lc)

#include <asm/termbits.h>  /* Definition of TIOCCONS */
#include <sys/ioctl.h>
int ioctl(int fd, TIOCCONS);

Redirect output that would have gone to /dev/console or /dev/tty0 to the given terminal. If that was a pseudoterminal master, send it to the slave.

Only a process with the CAP_SYS_ADMIN capability may do this.

If output was redirected already, then EBUSY is returned, but redirection can be stopped by using this ioctl with fd pointing at /dev/console or /dev/tty0.

On success, 0 is returned. On error, -1 is returned, and errno is set to indicate the error.

Output was redirected already.
Insufficient permission.

Before Linux 2.6.10, anybody can do this as long as the output was not redirected yet; CAP_SYS_ADMIN was not necessary.

ioctl(2), ioctl_tty(2)

2024-06-13 Linux man-pages 6.9.1