HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. |  |
NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |ERRORS |STANDARDS |SEE ALSO |COLOPHON | |
ioctl_kd(2) System Calls Manualioctl_kd(2)ioctl_kd - ioctls for console terminal and virtual consoles
#include <linux/kd.h>/* Definition of op constants */#include <sys/ioctl.h>int ioctl(intfd, unsigned longop, void *argp);
The following Linux-specificioctl(2) operations are supported for console terminals and virtual consoles.KDGETLED Get state of LEDs.argp points to achar. The lower three bits of*argp are set to the state of the LEDs, as follows: LED_CAP 0x04 caps lock led LED_NUM 0x02 num lock led LED_SCR 0x01 scroll lock ledKDSETLED Set the LEDs. The LEDs are set to correspond to the lower three bits of the unsigned long integer inargp. 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. 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.KDGKBLED Get keyboard flags CapsLock, NumLock, ScrollLock (not lights).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.)KDSKBLED Set keyboard flags CapsLock, NumLock, ScrollLock (not lights).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.)KDGKBTYPE Get keyboard type. This returns the value KB_101, defined as 0x02.KDADDIO Add I/O port as valid. Equivalent toioperm(arg,1,1).KDDELIO Delete I/O port as valid. Equivalent toioperm(arg,1,0).KDENABIO Enable I/O to video board. Equivalent toioperm(0x3b4,0x3df-0x3b4+1, 1).KDDISABIO Disable I/O to video board. Equivalent toioperm(0x3b4,0x3df-0x3b4+1, 0).KDSETMODE Set text/graphics mode.argp is an unsigned integer containing one of: KD_TEXT 0x00 KD_GRAPHICS 0x01KDGETMODE Get text/graphics mode.argp points to anint which is set to one of the values shown above forKDSETMODE.KDMKTONE Generate tone of specified length. The lower 16 bits of the unsigned long integer inargp 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,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.)KIOCSOUND Start or stop sound generation. The lower 16 bits ofargp specify the period in clock cycles (that is,argp = 1193180/frequency).argp = 0 turns sound off. In either case, control returns immediately.GIO_CMAP Get the current default color map from kernel.argp points to a 48-byte array. (Since Linux 1.3.3.)PIO_CMAP Change the default text-mode color map.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.)GIO_FONT Gets 256-character screen font in expanded form.argp points to an 8192-byte array. Fails with error codeEINVAL if the currently loaded font is a 512-character font, or if the console is not in text mode.GIO_FONTX Gets screen font and associated information.argp points to astruct consolefontdesc (seePIO_FONTX). On call, thecharcount field should be set to the maximum number of characters that would fit in the buffer pointed to bychardata. On return, thecharcount andcharheight are filled with the respective data for the currently loaded font, and thechardata array contains the font data if the initial value ofcharcount indicated enough space was available; otherwise the buffer is untouched anderrno is set toENOMEM. (Since Linux 1.3.1.)PIO_FONT Sets 256-character screen font. Load font into the EGA/VGA character generator.argp points to an 8192-byte map, with 32 bytes per character. Only the firstN of them are used for an 8xN font (0 <N <= 32). This call also invalidates the Unicode mapping.PIO_FONTX Sets screen font and associated rendering information.argp points to a 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 */ }; If necessary, the screen will be appropriately resized, andSIGWINCHsent to the appropriate processes. This call also invalidates the Unicode mapping. (Since Linux 1.3.1.)PIO_FONTRESET Resets the screen font, size, and Unicode mapping to the bootup defaults.argp is unused, but should be set to NULL to ensure compatibility with future versions of Linux. (Since Linux 1.3.28.)GIO_SCRNMAP Get screen mapping from kernel.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.GIO_UNISCRNMAP Get full Unicode screen mapping from kernel.argp points to an area of sizeE_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.)PIO_SCRNMAP Loads the "user definable" (fourth) table in the kernel which maps bytes into console screen symbols.argp points to an area of size E_TABSZ.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.)GIO_UNIMAP Get Unicode-to-font mapping from kernel.argp points to a struct unimapdesc { unsigned short entry_ct; struct unipair *entries; }; whereentries points to an array of struct unipair { unsigned short unicode; unsigned short fontpos; }; (Since Linux 1.1.92.)PIO_UNIMAP Put unicode-to-font mapping in kernel.argp points to astruct unimapdesc. (Since Linux 1.1.92)PIO_UNIMAPCLR Clear table, possibly advise hash algorithm.argp points to a 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 */ }; (Since Linux 1.1.92.)KDGKBMODE Gets current keyboard mode.argp points to along which is set to one of these: 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 */KDSKBMODE Sets current keyboard mode.argp is along equal to one of the values shown forKDGKBMODE.KDGKBMETA Gets meta key handling mode.argp points to along which is set to one of these: K_METABIT 0x03 set high order bit K_ESCPREFIX 0x04 escape prefixKDSKBMETA Sets meta key handling mode.argp is along equal to one of the values shown above forKDGKBMETA.KDGKBENT Gets one entry in key translation table (keycode to action code).argp points to a struct kbentry { unsigned char kb_table; unsigned char kb_index; unsigned short kb_value; }; with the first two members filled in:kb_table selects the key table (0 <=kb_table < MAX_NR_KEYMAPS), andkb_index is the keycode (0 <=kb_index < NR_KEYS).kb_value is set to the corresponding action code, or K_HOLE if there is no such key, or K_NOSUCHMAP ifkb_table is invalid.KDSKBENT Sets one entry in translation table.argp points to astruct kbentry.KDGKBSENT Gets one function key string.argp points to a struct kbsentry { unsigned char kb_func; unsigned char kb_string[512]; };kb_string is set to the (null-terminated) string corresponding to thekb_functh function key action code.KDSKBSENT Sets one function key string entry.argp points to astruct kbsentry.KDGKBDIACR Read kernel accent table.argp points to a struct kbdiacrs { unsigned int kb_cnt; struct kbdiacr kbdiacr[256]; }; wherekb_cnt is the number of entries in the array, each of which is a struct kbdiacr { unsigned char diacr; unsigned char base; unsigned char result; };KDGETKEYCODE Read kernel keycode table entry (scan code to keycode).argp points to a struct kbkeycode { unsigned int scancode; unsigned int keycode; };keycode is set to correspond to the givenscancode. (89 <=scancode <= 255 only. For 1 <=scancode <= 88,keycode==scancode.) (Since Linux 1.1.63.)KDSETKEYCODE Write kernel keycode table entry.argp points to astructkbkeycode. (Since Linux 1.1.63.)KDSIGACCEPT The calling process indicates its willingness to accept the signalargp when it is generated by pressing an appropriate key combination. (1 <=argp <= NSIG). (Seespawn_console() inlinux/drivers/char/keyboard.c.)On success, 0 is returned (except where indicated). On failure, -1 is returned, anderrno is set to indicate the error.
EINVALargp is invalid.
Linux.
ioctl(2),ioctl_console(2)
This page is part of theman-pages (Linux kernel and C library user-space interface documentation) project. Information about the project can be found at ⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report for this manual page, see ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩. This page was obtained from the tarball man-pages-6.15.tar.gz fetched from ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on 2025-08-11. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgLinux man-pages 6.15 2025-05-17ioctl_kd(2)Pages that refer to this page:ioctl_console(2)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |