2.9BSD/usr/man/cat2/ioctl.2

IOCTL(2)            UNIX Programmer's 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
     _I_o_c_t_l performs a variety of functions on character special
     files (devices).  The writeups of various devices in section
     4 discuss how _i_o_c_t_l applies to them.

     For certain status setting and status inquiries about termi-
     nal devices, the functions _s_t_t_y and _g_t_t_y are equivalent to
          ioctl(fildes, TIOCSETP, argp)
          ioctl(fildes, TIOCGETP, argp)

     respectively; see _t_t_y(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 _e_x_e_c operation; the second reverses the effect
     of the first.

RETURN VALUE
     Upon successful completion, a value of 0 is returned.  Oth-
     erwise, a value of -1 is returned and _e_r_r_n_o is set to indi-
     cate the error.

ERRORS
     _I_o_c_t_l will fail if one or more of the following is true:

     [EBADF]             _F_i_l_d_e_s is not a valid descriptor.

     [ENOTTY]            _F_i_l_d_e_s is not associated with a charac-
                         ter special device.

     [ENOTTY]            The specified request does not apply to
                         the kind of object that the descriptor
                         _f_i_l_d_e_s references.

Printed 5/26/83                                                 1

IOCTL(2)            UNIX Programmer's Manual             IOCTL(2)

     [EINVAL]            _R_e_q_u_e_s_t or _a_r_g_p is not valid.

SEE ALSO
     stty(1), execve(2), exec(3), tty(4)

BUGS
     Strictly speaking, since _i_o_c_t_l may be extended in different
     ways to devices with different properties, _a_r_g_p should have
     an open-ended declaration 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

Printed 5/26/83                                                 2