ioctl_vt(2)

✨ ioctl_vt — bestie's guide to console + virtual console ioctls ✨

okay so this is a page from the System Calls Manual (section 2, the real ones 💅), and it's literally all about ioctl_vt — the ioctls that let you talk to console terminals and virtual consoles on Linux. no cap, this is Linux-specific stuff only. let's get into it 🎀

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💖 NAME 💖

ioctl_vt — ioctls for console terminal and virtual consoles

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🌸 SYNOPSIS 🌸

#include <linux/vt.h>  /* Definition of VT_* constants */
#include <sys/ioctl.h>

int ioctl(int fd, unsigned long op, void *argp);

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🦋 DESCRIPTION 🦋

The following Linux-specific ioctl(2) operations are supported for console terminals and virtual consoles. slay, let's go one by one 🫶

• VT_OPENQRY — hands you the first available (aka non-opened) console. argp points to an int which gets set to the number of the vt (1 <= *argp <= MAX_NR_CONSOLES). it's giving "who's free rn" energy.
• VT_GETMODE — get the mode of the 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 gets set to the mode of the active vt. and mode gets set to one of these values, periodt:

• VT_AUTO — auto vt switching
• VT_PROCESS — process controls switching
• VT_ACKACQ — acknowledge switch

• VT_SETMODE — set the mode of the active vt. argp points to a struct vt_mode. iconic.
• 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 that's in use, the corresponding bit in the v_state member gets set. (Linux 1.0 through Linux 1.1.92.) 🕰️

• VT_RELDISP — release a display. bye bestie 👋
• VT_ACTIVATE — switch to vt argp (1 <= argp <= MAX_NR_CONSOLES).
• VT_WAITACTIVE — wait until vt argp has been activated. the way it just... sits there until the switch happens 😭
• 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 */
};

heads up bestie: 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, which means "no change" — but if multiple parameters get set, they must be self-consistent. no chaotic mismatched vibes allowed 🙈

also: 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.) brand new, fresh off the press ✨

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👑 RETURN VALUE 👑

On success, 0 is returned (except where indicated). On failure, -1 is returned, and errno is set to indicate the error. so like, check errno, bestie, don't just assume 💀

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💅 ERRORS 💅

• EINVAL — argp is invalid.

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🌈 STANDARDS 🌈

Linux. (we're not doing POSIX today, this is Linux-specific, iykyk 🐧)

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🔥 SEE ALSO 🔥

• ioctl(2)
• ioctl_console(2)

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so that's the whole thing, no notes 🧚

source/version situation: this page is from Linux man-pages 6.20, dated 2026-02-08. go off, man-pages team 💖💜

bye bestie, go resize some consoles responsibly 🎀