Merging upstream version 6.8.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 915 insertions, 0 deletions

diff --git a/man/man2/ioctl_console.2 b/man/man2/ioctl_console.2
new file mode 100644
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+'\" t
+.\" Copyright (c) 1995 Jim Van Zandt <jrv@vanzandt.mv.com> and aeb
+.\" Sun Feb 26 11:46:23 MET 1995
+.\"
+.\" SPDX-License-Identifier: GPL-2.0-or-later
+.\"
+.\" Modified, Sun Feb 26 15:04:20 1995, faith@cs.unc.edu
+.\" Modified, Thu Apr 20 22:08:17 1995, jrv@vanzandt.mv.com
+.\" Modified, Mon Sep 18 22:32:47 1995, hpa@storm.net (H. Peter Anvin)
+.\" FIXME The following are not documented:
+.\"     KDFONTOP (since Linux 2.1.111)
+.\"     KDGKBDIACRUC (since Linux 2.6.24)
+.\"     KDSKBDIACR
+.\"     KDSKBDIACRUC (since Linux 2.6.24)
+.\"     KDKBDREP (since Linux 2.1.113)
+.\"     KDMAPDISP (not implemented as at Linux 2.6.27)
+.\"     KDUNMAPDISP (not implemented as at Linux 2.6.27)
+.\"     VT_LOCKSWITCH (since Linux 1.3.47, needs CAP_SYS_TTY_CONFIG)
+.\"     VT_UNLOCKSWITCH (since Linux 1.3.47, needs CAP_SYS_TTY_CONFIG)
+.\"     VT_GETHIFONTMASK (since Linux 2.6.18)
+.\"
+.TH ioctl_console 2 2024-05-02 "Linux man-pages (unreleased)"
+.SH NAME
+ioctl_console \- ioctls for console terminal and virtual consoles
+.SH DESCRIPTION
+The following Linux-specific
+.BR ioctl (2)
+operations are supported for console terminals and virtual consoles.
+Each operation requires a third argument, assumed here to be
+.IR argp .
+.TP
+.B KDGETLED
+Get state of LEDs.
+.I argp
+points to a
+.IR char .
+The lower three bits
+of
+.I *argp
+are set to the state of the LEDs, as follows:
+.TS
+l l l.
+LED_CAP 	0x04	caps lock led
+LED_NUM 	0x02	num lock led
+LED_SCR 	0x01	scroll lock led
+.TE
+.TP
+.B KDSETLED
+Set the LEDs.
+The LEDs are set to correspond to the lower three bits of the
+unsigned long integer in
+.IR argp .
+However, if a higher order bit is set,
+the LEDs revert to normal: displaying the state of the
+keyboard functions of caps lock, num lock, and scroll lock.
+.P
+Before Linux 1.1.54, the LEDs just reflected the state of the corresponding
+keyboard flags, and KDGETLED/KDSETLED would also change the keyboard
+flags.
+Since Linux 1.1.54 the LEDs can be made to display arbitrary
+information, but by default they display the keyboard flags.
+The following two ioctls are used to access the keyboard flags.
+.TP
+.B KDGKBLED
+Get keyboard flags CapsLock, NumLock, ScrollLock (not lights).
+.I argp
+points to a char which is set to the flag state.
+The low order three bits (mask 0x7) get the current flag state,
+and the low order bits of the next nibble (mask 0x70) get
+the default flag state.
+(Since Linux 1.1.54.)
+.TP
+.B KDSKBLED
+Set keyboard flags CapsLock, NumLock, ScrollLock (not lights).
+.I argp
+is an unsigned long integer that has the desired flag state.
+The low order three bits (mask 0x7) have the flag state,
+and the low order bits of the next nibble (mask 0x70) have
+the default flag state.
+(Since Linux 1.1.54.)
+.TP
+.B KDGKBTYPE
+Get keyboard type.
+This returns the value KB_101, defined as 0x02.
+.TP
+.B KDADDIO
+Add I/O port as valid.
+Equivalent to
+.IR ioperm(arg,1,1) .
+.TP
+.B KDDELIO
+Delete I/O port as valid.
+Equivalent to
+.IR ioperm(arg,1,0) .
+.TP
+.B KDENABIO
+Enable I/O to video board.
+Equivalent to
+.IR "ioperm(0x3b4, 0x3df\-0x3b4+1, 1)" .
+.TP
+.B KDDISABIO
+Disable I/O to video board.
+Equivalent to
+.IR "ioperm(0x3b4, 0x3df\-0x3b4+1, 0)" .
+.TP
+.B KDSETMODE
+Set text/graphics mode.
+.I argp
+is an unsigned integer containing one of:
+.TS
+l l.
+KD_TEXT	0x00
+KD_GRAPHICS	0x01
+.TE
+.TP
+.B KDGETMODE
+Get text/graphics mode.
+.I argp
+points to an
+.I int
+which is set to one
+of the values shown above for
+.BR KDSETMODE .
+.TP
+.B KDMKTONE
+Generate tone of specified length.
+The lower 16 bits of the unsigned long integer in
+.I argp
+specify the period in clock cycles,
+and the upper 16 bits give the duration in msec.
+If the duration is zero, the sound is turned off.
+Control returns immediately.
+For example,
+.I argp
+= (125<<16) + 0x637 would specify
+the beep normally associated with a ctrl-G.
+(Thus since Linux 0.99pl1; broken in Linux 2.1.49-50.)
+.TP
+.B KIOCSOUND
+Start or stop sound generation.
+The lower 16 bits of
+.I argp
+specify the period in clock cycles
+(that is,
+.I argp
+= 1193180/frequency).
+.I argp
+= 0 turns sound off.
+In either case, control returns immediately.
+.TP
+.B GIO_CMAP
+Get the current default color map from kernel.
+.I argp
+points to
+a 48-byte array.
+(Since Linux 1.3.3.)
+.TP
+.B PIO_CMAP
+Change the default text-mode color map.
+.I argp
+points to a
+48-byte array which contains, in order, the Red, Green, and Blue
+values for the 16 available screen colors: 0 is off, and 255 is full
+intensity.
+The default colors are, in order: black, dark red, dark
+green, brown, dark blue, dark purple, dark cyan, light grey, dark
+grey, bright red, bright green, yellow, bright blue, bright purple,
+bright cyan, and white.
+(Since Linux 1.3.3.)
+.TP
+.B GIO_FONT
+Gets 256-character screen font in expanded form.
+.I argp
+points to an 8192-byte array.
+Fails with error code
+.B EINVAL
+if the
+currently loaded font is a 512-character font, or if the console is
+not in text mode.
+.TP
+.B GIO_FONTX
+Gets screen font and associated information.
+.I argp
+points to a
+.I "struct consolefontdesc"
+(see
+.BR PIO_FONTX ).
+On call, the
+.I charcount
+field should be set to the maximum number of
+characters that would fit in the buffer pointed to by
+.IR chardata .
+On return, the
+.I charcount
+and
+.I charheight
+are filled with
+the respective data for the currently loaded font, and the
+.I chardata
+array contains the font data if the initial value of
+.I charcount
+indicated enough space was available; otherwise the
+buffer is untouched and
+.I errno
+is set to
+.BR ENOMEM .
+(Since Linux 1.3.1.)
+.TP
+.B PIO_FONT
+Sets 256-character screen font.
+Load font into the EGA/VGA character
+generator.
+.I argp
+points to an 8192-byte map, with 32 bytes per
+character.
+Only the first
+.I N
+of them are used for an 8x\fIN\fP font
+(0 <
+.I N
+<= 32).
+This call also invalidates the Unicode mapping.
+.TP
+.B PIO_FONTX
+Sets screen font and associated rendering information.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct consolefontdesc {
+    unsigned short charcount;  /* characters in font
+                                  (256 or 512) */
+    unsigned short charheight; /* scan lines per
+                                  character (1\-32) */
+    char          *chardata;   /* font data in
+                                  expanded form */
+};
+.EE
+.in
+.IP
+If necessary, the screen will be appropriately resized, and
+.B SIGWINCH
+sent to the appropriate processes.
+This call also invalidates the Unicode mapping.
+(Since Linux 1.3.1.)
+.TP
+.B PIO_FONTRESET
+Resets the screen font, size, and Unicode mapping to the bootup
+defaults.
+.I argp
+is unused, but should be set to NULL to
+ensure compatibility with future versions of Linux.
+(Since Linux 1.3.28.)
+.TP
+.B GIO_SCRNMAP
+Get screen mapping from kernel.
+.I argp
+points to an area of size
+E_TABSZ, which is loaded with the font positions used to display each
+character.
+This call is likely to return useless information if the
+currently loaded font is more than 256 characters.
+.TP
+.B GIO_UNISCRNMAP
+Get full Unicode screen mapping from kernel.
+.I argp
+points to an
+area of size
+.IR "E_TABSZ*sizeof(unsigned short)" ,
+which is loaded with the
+Unicodes each character represent.
+A special set of Unicodes,
+starting at U+F000, are used to represent "direct to font" mappings.
+(Since Linux 1.3.1.)
+.TP
+.B PIO_SCRNMAP
+Loads the "user definable" (fourth) table in the kernel which maps
+bytes into console screen symbols.
+.I argp
+points to an area of
+size E_TABSZ.
+.TP
+.B PIO_UNISCRNMAP
+Loads the "user definable" (fourth) table in the kernel which maps
+bytes into Unicodes, which are then translated into screen symbols
+according to the currently loaded Unicode-to-font map.
+Special Unicodes starting at U+F000 can be used to map directly to the font
+symbols.
+(Since Linux 1.3.1.)
+.TP
+.B GIO_UNIMAP
+Get Unicode-to-font mapping from kernel.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct unimapdesc {
+    unsigned short  entry_ct;
+    struct unipair *entries;
+};
+.EE
+.in
+.IP
+where
+.I entries
+points to an array of
+.IP
+.in +4n
+.EX
+struct unipair {
+    unsigned short unicode;
+    unsigned short fontpos;
+};
+.EE
+.in
+.IP
+(Since Linux 1.1.92.)
+.TP
+.B PIO_UNIMAP
+Put unicode-to-font mapping in kernel.
+.I argp
+points to a
+.IR "struct unimapdesc" .
+(Since Linux 1.1.92)
+.TP
+.B PIO_UNIMAPCLR
+Clear table, possibly advise hash algorithm.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct unimapinit {
+    unsigned short advised_hashsize;  /* 0 if no opinion */
+    unsigned short advised_hashstep;  /* 0 if no opinion */
+    unsigned short advised_hashlevel; /* 0 if no opinion */
+};
+.EE
+.in
+.IP
+(Since Linux 1.1.92.)
+.TP
+.B KDGKBMODE
+Gets current keyboard mode.
+.I argp
+points to a
+.I long
+which is set to one
+of these:
+.TS
+l l.
+K_RAW	0x00  /* Raw (scancode) mode */
+K_XLATE	0x01  /* Translate keycodes using keymap */
+K_MEDIUMRAW	0x02  /* Medium raw (scancode) mode */
+K_UNICODE	0x03  /* Unicode mode */
+K_OFF	0x04  /* Disabled mode; since Linux 2.6.39 */
+.\" K_OFF: commit 9fc3de9c83565fcaa23df74c2fc414bb6e7efb0a
+.TE
+.TP
+.B KDSKBMODE
+Sets current keyboard mode.
+.I argp
+is a
+.I long
+equal to one of the values shown for
+.BR KDGKBMODE .
+.TP
+.B KDGKBMETA
+Gets meta key handling mode.
+.I argp
+points to a
+.I long
+which is
+set to one of these:
+.TS
+l l l.
+K_METABIT	0x03	set high order bit
+K_ESCPREFIX	0x04	escape prefix
+.TE
+.TP
+.B KDSKBMETA
+Sets meta key handling mode.
+.I argp
+is a
+.I long
+equal to one of the values shown above for
+.BR KDGKBMETA .
+.TP
+.B KDGKBENT
+Gets one entry in key translation table (keycode to action code).
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct kbentry {
+    unsigned char  kb_table;
+    unsigned char  kb_index;
+    unsigned short kb_value;
+};
+.EE
+.in
+.IP
+with the first two members filled in:
+.I kb_table
+selects the key table (0 <=
+.I kb_table
+< MAX_NR_KEYMAPS),
+and
+.I kb_index
+is the keycode (0 <=
+.I kb_index
+< NR_KEYS).
+.I kb_value
+is set to the corresponding action code,
+or K_HOLE if there is no such key,
+or K_NOSUCHMAP if
+.I kb_table
+is invalid.
+.TP
+.B KDSKBENT
+Sets one entry in translation table.
+.I argp
+points to a
+.IR "struct kbentry" .
+.TP
+.B KDGKBSENT
+Gets one function key string.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct kbsentry {
+    unsigned char kb_func;
+    unsigned char kb_string[512];
+};
+.EE
+.in
+.IP
+.I kb_string
+is set to the (null-terminated) string corresponding to
+the
+.IR kb_func th
+function key action code.
+.TP
+.B KDSKBSENT
+Sets one function key string entry.
+.I argp
+points to a
+.IR "struct kbsentry" .
+.TP
+.B KDGKBDIACR
+Read kernel accent table.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct kbdiacrs {
+    unsigned int   kb_cnt;
+    struct kbdiacr kbdiacr[256];
+};
+.EE
+.in
+.IP
+where
+.I kb_cnt
+is the number of entries in the array, each of which
+is a
+.IP
+.in +4n
+.EX
+struct kbdiacr {
+    unsigned char diacr;
+    unsigned char base;
+    unsigned char result;
+};
+.EE
+.in
+.TP
+.B KDGETKEYCODE
+Read kernel keycode table entry (scan code to keycode).
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct kbkeycode {
+    unsigned int scancode;
+    unsigned int keycode;
+};
+.EE
+.in
+.IP
+.I keycode
+is set to correspond to the given
+.IR scancode .
+(89 <=
+.I scancode
+<= 255 only.
+For 1 <=
+.I scancode
+<= 88,
+.IR keycode == scancode .)
+(Since Linux 1.1.63.)
+.TP
+.B KDSETKEYCODE
+Write kernel keycode table entry.
+.I argp
+points to a
+.IR "struct kbkeycode" .
+(Since Linux 1.1.63.)
+.TP
+.B KDSIGACCEPT
+The calling process indicates its willingness to accept the signal
+.I argp
+when it is generated by pressing an appropriate key combination.
+(1 <=
+.I argp
+<= NSIG).
+(See
+.IR spawn_console ()
+in
+.IR linux/drivers/char/keyboard.c .)
+.TP
+.B VT_OPENQRY
+Returns the first available (non-opened) console.
+.I argp
+points to an
+.I int
+which is set to the
+number of the vt (1 <=
+.I *argp
+<= MAX_NR_CONSOLES).
+.TP
+.B VT_GETMODE
+Get mode of active vt.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+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) */
+};
+.EE
+.in
+.IP
+which is set to the mode of the active vt.
+.I mode
+is set to one of these values:
+.TS
+l l.
+VT_AUTO	auto vt switching
+VT_PROCESS	process controls switching
+VT_ACKACQ	acknowledge switch
+.TE
+.TP
+.B VT_SETMODE
+Set mode of active vt.
+.I argp
+points to a
+.IR "struct vt_mode" .
+.TP
+.B VT_GETSTATE
+Get global vt state info.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct vt_stat {
+    unsigned short v_active;  /* active vt */
+    unsigned short v_signal;  /* signal to send */
+    unsigned short v_state;   /* vt bit mask */
+};
+.EE
+.in
+.IP
+For each vt in use, the corresponding bit in the
+.I v_state
+member is set.
+(Linux 1.0 through Linux 1.1.92.)
+.TP
+.B VT_RELDISP
+Release a display.
+.TP
+.B VT_ACTIVATE
+Switch to vt
+.I argp
+(1 <=
+.I argp
+<= MAX_NR_CONSOLES).
+.TP
+.B VT_WAITACTIVE
+Wait until vt
+.I argp
+has been activated.
+.TP
+.B VT_DISALLOCATE
+Deallocate the memory associated with vt
+.IR argp .
+(Since Linux 1.1.54.)
+.TP
+.B VT_RESIZE
+Set the kernel's idea of screensize.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct vt_sizes {
+    unsigned short v_rows;       /* # rows */
+    unsigned short v_cols;       /* # columns */
+    unsigned short v_scrollsize; /* no longer used */
+};
+.EE
+.in
+.IP
+Note that this does not change the videomode.
+See
+.BR resizecons (8).
+(Since Linux 1.1.54.)
+.TP
+.B VT_RESIZEX
+Set the kernel's idea of various screen parameters.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+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 */
+};
+.EE
+.in
+.IP
+Any parameter may be set to zero, indicating "no change", but if
+multiple parameters are set, they must be self-consistent.
+Note that this does not change the videomode.
+See
+.BR resizecons (8).
+(Since Linux 1.3.3.)
+.P
+The action of the following ioctls depends on the first byte in the struct
+pointed to by
+.IR argp ,
+referred to here as the
+.IR subcode .
+These are legal only for the superuser or the owner of the current terminal.
+Symbolic
+.IR subcode s
+are available in
+.I <linux/tiocl.h>
+since
+Linux 2.5.71.
+.TP
+.BR TIOCLINUX ", " subcode = 0
+Dump the screen.
+Disappeared in Linux 1.1.92.
+(With Linux 1.1.92 or later, read from
+.I /dev/vcsN
+or
+.I /dev/vcsaN
+instead.)
+.TP
+.BR TIOCLINUX ", " subcode = 1
+Get task information.
+Disappeared in Linux 1.1.92.
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_SETSEL
+Set selection.
+.I argp
+points to a
+.IP
+.in +4n
+.EX
+struct {
+    char  subcode;
+    short xs, ys, xe, ye;
+    short sel_mode;
+};
+.EE
+.in
+.IP
+.I xs
+and
+.I ys
+are the starting column and row.
+.I xe
+and
+.I ye
+are the ending
+column and row.
+(Upper left corner is row=column=1.)
+.I sel_mode
+is 0 for character-by-character selection,
+1 for word-by-word selection,
+or 2 for line-by-line selection.
+The indicated screen characters are highlighted and saved
+in a kernel buffer.
+.IP
+Since Linux 6.7, using this subcode requires the
+.B CAP_SYS_ADMIN
+capability.
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_PASTESEL
+Paste selection.
+The characters in the selection buffer are
+written to
+.IR fd .
+.IP
+Since Linux 6.7, using this subcode requires the
+.B CAP_SYS_ADMIN
+capability.
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_UNBLANKSCREEN
+Unblank the screen.
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_SELLOADLUT
+Sets contents of a 256-bit look up table defining characters in a "word",
+for word-by-word selection.
+(Since Linux 1.1.32.)
+.IP
+Since Linux 6.7, using this subcode requires the
+.B CAP_SYS_ADMIN
+capability.
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_GETSHIFTSTATE
+.I argp
+points to a char which is set to the value of the kernel
+variable
+.IR shift_state .
+(Since Linux 1.1.32.)
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_GETMOUSEREPORTING
+.I argp
+points to a char which is set to the value of the kernel
+variable
+.IR report_mouse .
+(Since Linux 1.1.33.)
+.TP
+.BR TIOCLINUX ", " subcode = 8
+Dump screen width and height, cursor position, and all the
+character-attribute pairs.
+(Linux 1.1.67 through Linux 1.1.91 only.
+With Linux 1.1.92 or later, read from
+.I /dev/vcsa*
+instead.)
+.TP
+.BR TIOCLINUX ", " subcode = 9
+Restore screen width and height, cursor position, and all the
+character-attribute pairs.
+(Linux 1.1.67 through Linux 1.1.91 only.
+With Linux 1.1.92 or later, write to
+.I /dev/vcsa*
+instead.)
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_SETVESABLANK
+Handles the Power Saving
+feature of the new generation of monitors.
+VESA screen blanking mode is set to
+.IR argp[1] ,
+which governs what
+screen blanking does:
+.RS
+.TP
+.B 0
+Screen blanking is disabled.
+.TP
+.B 1
+The current video adapter
+register settings are saved, then the controller is programmed to turn off
+the vertical synchronization pulses.
+This puts the monitor into "standby" mode.
+If your monitor has an Off_Mode timer, then
+it will eventually power down by itself.
+.TP
+.B 2
+The current settings are saved, then both the vertical and horizontal
+synchronization pulses are turned off.
+This puts the monitor into "off" mode.
+If your monitor has no Off_Mode timer,
+or if you want your monitor to power down immediately when the
+blank_timer times out, then you choose this option.
+.RI ( Caution:
+Powering down frequently will damage the monitor.)
+(Since Linux 1.1.76.)
+.RE
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_SETKMSGREDIRECT
+Change target of kernel messages ("console"):
+by default, and if this is set to
+.BR 0 ,
+messages are written to the currently active VT.
+The VT to write to is a single byte following
+.BR subcode .
+(Since Linux 2.5.36.)
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_GETFGCONSOLE
+Returns the number of VT currently in foreground.
+(Since Linux 2.5.36.)
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_SCROLLCONSOLE
+Scroll the foreground VT by the specified amount of
+.I lines
+down,
+or half the screen if
+.BR 0 .
+.I lines
+is *(((int32_t *)&subcode) + 1).
+(Since Linux 2.5.67.)
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_BLANKSCREEN
+Blank the foreground VT, ignoring "pokes" (typing):
+can only be unblanked explicitly (by switching VTs, to text mode, etc.).
+(Since Linux 2.5.71.)
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_BLANKEDSCREEN
+Returns the number of VT currently blanked,
+.B 0
+if none.
+(Since Linux 2.5.71.)
+.TP
+.BR TIOCLINUX ", " subcode = 16
+Never used.
+.TP
+.BR TIOCLINUX ", " subcode = TIOCL_GETKMSGREDIRECT
+Returns target of kernel messages.
+(Since Linux 2.6.17.)
+.SH RETURN VALUE
+On success, 0 is returned (except where indicated).
+On failure, \-1 is returned, and
+.I errno
+is set to indicate the error.
+.SH ERRORS
+.TP
+.B EBADF
+The file descriptor is invalid.
+.TP
+.B EINVAL
+The file descriptor or
+.I argp
+is invalid.
+.TP
+.B ENOTTY
+The file descriptor is not associated with a character special device,
+or the specified operation does not apply to it.
+.TP
+.B EPERM
+Insufficient permission.
+.SH NOTES
+.BR Warning :
+Do not regard this man page as documentation of the Linux console ioctls.
+This is provided for the curious only, as an alternative to reading the
+source.
+Ioctl's are undocumented Linux internals, liable to be changed
+without warning.
+(And indeed, this page more or less describes the
+situation as of kernel version 1.1.94;
+there are many minor and not-so-minor
+differences with earlier versions.)
+.P
+Very often, ioctls are introduced for communication between the
+kernel and one particular well-known program (fdisk, hdparm, setserial,
+tunelp, loadkeys, selection, setfont, etc.), and their behavior will be
+changed when required by this particular program.
+.P
+Programs using these ioctls will not be portable to other versions
+of UNIX, will not work on older versions of Linux, and will not work
+on future versions of Linux.
+.P
+Use POSIX functions.
+.SH SEE ALSO
+.BR dumpkeys (1),
+.BR kbd_mode (1),
+.BR loadkeys (1),
+.BR mknod (1),
+.BR setleds (1),
+.BR setmetamode (1),
+.BR execve (2),
+.BR fcntl (2),
+.BR ioctl_tty (2),
+.BR ioperm (2),
+.BR termios (3),
+.BR console_codes (4),
+.BR mt (4),
+.BR sd (4),
+.BR tty (4),
+.BR ttyS (4),
+.BR vcs (4),
+.BR vcsa (4),
+.BR charsets (7),
+.BR mapscrn (8),
+.BR resizecons (8),
+.BR setfont (8)
+.P
+.IR /usr/include/linux/kd.h ,
+.I /usr/include/linux/vt.h