TIOCCONS - redirecting console output

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.

EBUSY Output was redirected already. EPERM 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.

Standard C library (libc, -lc)

TIOCCONS - redirecting console output

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

ioctl(2), ioctl_tty(2) Linux man-pages 6.9.1 2024-06-13 TIOCCONS(2const)

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