TIOCSCTTY(2const)                                            TIOCSCTTY(2const)

NAME
       TIOCSCTTY, TIOCNOTTY - controlling the terminal

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <asm/termbits.h>  /* Definition of TIOC*TTY constants */
       #include <sys/ioctl.h>

       int ioctl(int fd, TIOCSCTTY, int arg);
       int ioctl(int fd, TIOCNOTTY);

DESCRIPTION
       TIOCSCTTY
              Make the given terminal the controlling terminal of the calling
              process.  The calling process must be a session leader and not
              have a controlling terminal already.  For this case, arg should
              be specified as zero.

              If this terminal is already the controlling terminal of a
              different session group, then the ioctl fails with EPERM, unless
              the caller has the CAP_SYS_ADMIN capability and arg equals 1, in
              which case the terminal is stolen, and all processes that had it
              as controlling terminal lose it.

       TIOCNOTTY
              If the given terminal was the controlling terminal of the
              calling process, give up this controlling terminal.  If the
              process was session leader, then send SIGHUP and SIGCONT to the
              foreground process group and all processes in the current
              session lose their controlling terminal.

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

ERRORS
       EPERM  Insufficient permission.

SEE ALSO
       ioctl(2), ioctl_tty(2)

Linux man-pages 6.18              2026-02-08                 TIOCSCTTY(2const)