www.LinuxHowtos.org

ioctl_vt

Section: System Calls (2)
Updated: 202-0-08
Index Return to Main Contents

NAME

ioctl_vt - ioctls for console terminal and virtual consoles

SYNOPSIS

#include <linux/vt.h>  /* Definition of VT_* constants */
#include <sys/ioctl.h>
int ioctl(int fd, unsigned long op, void *argp);

DESCRIPTION

The following Linu-specific ioctl(2) operations are supported for console terminals and virtual consoles.

VT_OPENQRY

Returns the first available (no-opened) console. argp points to an int which is set to the number of the vt (1 <= *argp <= MAX_NR_CONSOLES).

VT_GETMODE

Get mode of active vt. argp points to a

struct vt_mode {
    char  mode;    /* vt mode */
    char  waitv;   /* if set, hang on writes if not active */
    short relsig;  /* signal to raise on release op */
    short acqsig;  /* signal to raise on acquisition */
    short frsig;   /* unused (set to 0) */ };

which is set to the mode of the active vt. mode is set to one of these values:

VT_AUTO	auto vt switching
VT_PROCESS	process controls switching
VT_ACKACQ	acknowledge switch

VT_SETMODE

Set mode of active vt. argp points to a struct vt_mode.

VT_GETSTATE

Get global vt state info. argp points to a

struct vt_stat {
    unsigned short v_active;  /* active vt */
    unsigned short v_signal;  /* signal to send */
    unsigned short v_state;   /* vt bit mask */ };

For each vt in use, the corresponding bit in the v_state member is set. (Linux 1.0 through Linux 1.1.92.)

VT_RELDISP

Release a display.

VT_ACTIVATE

Switch to vt argp (1 <= argp <= MAX_NR_CONSOLES).

VT_WAITACTIVE

Wait until vt argp has been activated.

VT_DISALLOCATE

Deallocate the memory associated with vt argp. (Since Linux 1.1.54.)

VT_RESIZE

Set the kernel's idea of screensize. argp points to a

struct vt_sizes {
    unsigned short v_rows;       /* # rows */
    unsigned short v_cols;       /* # columns */
    unsigned short v_scrollsize; /* no longer used */ };

Note that this does not change the videomode. See resizecons(8). (Since Linux 1.1.54.)

VT_RESIZEX

Set the kernel's idea of various screen parameters. argp points to a

struct vt_consize {
    unsigned short v_rows;  /* number of rows */
    unsigned short v_cols;  /* number of columns */
    unsigned short v_vlin;  /* number of pixel rows
                               on screen */
    unsigned short v_clin;  /* number of pixel rows
                               per character */
    unsigned short v_vcol;  /* number of pixel columns
                               on screen */
    unsigned short v_ccol;  /* number of pixel columns
                               per character */ };

Any parameter may be set to zero, indicating "no change", but if multiple parameters are set, they must be sel-consistent. Note that this does not change the videomode. See resizecons(8). (Since Linux 1.3.3.)

VT_GETCONSIZECSRPOS

Get console size and cursor position. argp points to a

struct vt_consizecsrpos {
    __u16 con_rows;  /* number of console rows */
    __u16 con_cols;  /* number of console columns */
    __u16 csr_row;   /* current cursor's row */
    __u16 csr_col;   /* current cursor's column */ };

(Since Linux 6.16.)

RETURN VALUE

On success, 0 is returned (except where indicated). On failure, -1 is returned, and errno is set to indicate the error.

ERRORS

EINVAL: argp is invalid.

STANDARDS

Linux.