v7 man page for ioctl

IOCTL(2)							System Calls Manual							  IOCTL(2)

NAME
       ioctl, stty, gtty - control device

SYNOPSIS
       #include <sgtty.h>

       ioctl(fildes, request, argp)
       struct sgttyb *argp;

       stty(fildes, argp)
       struct sgttyb *argp;

       gtty(fildes, argp)
       struct sgttyb *argp;

DESCRIPTION
       Ioctl performs a variety of functions on character special files (devices).  The writeups of various devices in section 4 discuss how ioctl
       applies to them.

       For certain status setting and status inquiries about terminal devices, the functions stty and gtty are equivalent to
	      ioctl(fildes, TIOCSETP, argp)
	      ioctl(fildes, TIOCGETP, argp)

       respectively; see tty(4).

       The following two calls, however, apply to any open file:

	      ioctl(fildes, FIOCLEX, NULL);
	      ioctl(fildes, FIONCLEX, NULL);

       The first causes the file to be closed automatically during a successful exec operation; the second reverses the effect of the first.

SEE ALSO
       stty(1), tty(4), exec(2)

DIAGNOSTICS
       Zero is returned if the call was successful; -1 if the file descriptor does not refer to the kind of file for which it was intended.

BUGS
       Strictly speaking, since ioctl may be extended in different ways to devices with different properties, argp should have an open-ended  dec-
       laration like

	      union { struct sgttyb ...; ...  } *argp;

       The important thing is that the size is fixed by `struct sgttyb'.

ASSEMBLER
       (ioctl = 54.)
       sys ioctl; fildes; request; argp

       (stty = 31.)
       (file descriptor in r0)
       stty; argp

       (gtty = 32.)
       (file descriptor in r0)
       sys gtty; argp

																	  IOCTL(2)