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Diffstat (limited to 'man4/vcs.4')
| -rw-r--r-- | man4/vcs.4 | 172 |
1 files changed, 0 insertions, 172 deletions
diff --git a/man4/vcs.4 b/man4/vcs.4 deleted file mode 100644 index bf5dba2..0000000 --- a/man4/vcs.4 +++ /dev/null @@ -1,172 +0,0 @@ -.\" Copyright (c) 1995 James R. Van Zandt <jrv@vanzandt.mv.com> -.\" Sat Feb 18 09:11:07 EST 1995 -.\" -.\" SPDX-License-Identifier: GPL-2.0-or-later -.\" -.\" Modified, Sun Feb 26 15:08:05 1995, faith@cs.unc.edu -.\" 2007-12-17, Samuel Thibault <samuel.thibault@ens-lyon.org>: -.\" document the VT_GETHIFONTMASK ioctl -.\" " -.TH vcs 4 2023-10-31 "Linux man-pages 6.7" -.SH NAME -vcs, vcsa \- virtual console memory -.SH DESCRIPTION -.I /dev/vcs0 -is a character device with major number 7 and minor number -0, usually with mode 0644 and ownership root:tty. -It refers to the memory of the currently -displayed virtual console terminal. -.P -.I /dev/vcs[1\-63] -are character devices for virtual console -terminals, they have major number 7 and minor number 1 to 63, usually -mode 0644 and ownership root:tty. -.I /dev/vcsa[0\-63] -are the same, but -using -.IR "unsigned short" s -(in host byte order) that include attributes, -and prefixed with four bytes giving the screen -dimensions and cursor position: -.IR lines , -.IR columns , -.IR x , -.IR y . -.RI ( x -= -.I y -= 0 at the top left corner of the screen.) -.P -When a 512-character font is loaded, -the 9th bit position can be fetched by applying the -.BR ioctl (2) -.B VT_GETHIFONTMASK -operation -(available since Linux 2.6.18) -on -.IR /dev/tty[1\-63] ; -the value is returned in the -.I "unsigned short" -pointed to by the third -.BR ioctl (2) -argument. -.P -These devices replace the screendump -.BR ioctl (2) -operations of -.BR ioctl_console (2), -so the system -administrator can control access using filesystem permissions. -.P -The devices for the first eight virtual consoles may be created by: -.P -.in +4n -.EX -for x in 0 1 2 3 4 5 6 7 8; do - mknod \-m 644 /dev/vcs$x c 7 $x; - mknod \-m 644 /dev/vcsa$x c 7 $[$x+128]; -done -chown root:tty /dev/vcs* -.EE -.in -.P -No -.BR ioctl (2) -requests are supported. -.SH FILES -.I /dev/vcs[0\-63] -.br -.I /dev/vcsa[0\-63] -.\" .SH AUTHOR -.\" Andries Brouwer <aeb@cwi.nl> -.SH VERSIONS -Introduced with Linux 1.1.92. -.SH EXAMPLES -You may do a screendump on vt3 by switching to vt1 and typing -.P -.in +4n -.EX -cat /dev/vcs3 >foo -.EE -.in -.P -Note that the output does not contain -newline characters, so some processing may be required, like -in -.P -.in +4n -.EX -fold \-w 81 /dev/vcs3 | lpr -.EE -.in -.P -or (horrors) -.P -.in +4n -.EX -setterm \-dump 3 \-file /proc/self/fd/1 -.EE -.in -.P -The -.I /dev/vcsa0 -device is used for Braille support. -.P -This program displays the character and screen attributes under the -cursor of the second virtual console, then changes the background color -there: -.P -.EX -#include <unistd.h> -#include <stdlib.h> -#include <stdio.h> -#include <fcntl.h> -#include <sys/ioctl.h> -#include <linux/vt.h> -\& -int -main(void) -{ - int fd; - char *device = "/dev/vcsa2"; - char *console = "/dev/tty2"; - struct {unsigned char lines, cols, x, y;} scrn; - unsigned short s; - unsigned short mask; - unsigned char attrib; - int ch; -\& - fd = open(console, O_RDWR); - if (fd < 0) { - perror(console); - exit(EXIT_FAILURE); - } - if (ioctl(fd, VT_GETHIFONTMASK, &mask) < 0) { - perror("VT_GETHIFONTMASK"); - exit(EXIT_FAILURE); - } - (void) close(fd); - fd = open(device, O_RDWR); - if (fd < 0) { - perror(device); - exit(EXIT_FAILURE); - } - (void) read(fd, &scrn, 4); - (void) lseek(fd, 4 + 2*(scrn.y*scrn.cols + scrn.x), SEEK_SET); - (void) read(fd, &s, 2); - ch = s & 0xff; - if (s & mask) - ch |= 0x100; - attrib = ((s & \[ti]mask) >> 8); - printf("ch=%#03x attrib=%#02x\en", ch, attrib); - s \[ha]= 0x1000; - (void) lseek(fd, \-2, SEEK_CUR); - (void) write(fd, &s, 2); - exit(EXIT_SUCCESS); -} -.EE -.SH SEE ALSO -.BR ioctl_console (2), -.BR tty (4), -.BR ttyS (4), -.BR gpm (8) |