vga_safety_fork(3) [redhat man page]
vga_safety_fork(3) Svgalib User Manual vga_safety_fork(3) NAME
vga_safety_fork - start a parallel process to restore the console at a crash SYNOPSIS
#include <vga.h> void vga_safety_fork(void (*shutdown_routine)(void)) DESCRIPTION
Calling this at the start of a program results in a better chance of textmode being restored in case of a crash. However it has to raise the iopl level to 3 to work. This is a small security breach as it is inherited to any programs you fork of. However, some SVGA card driv- ers have to use iopl(3) anyway. If you use it call that function as the very first vga_ function. Call it right before vga_init (3). Note that vga_safety_fork() will already enter a graphicsmode. (For font and grafix state saving). Don't overestimate the power of this func- tion. Your application will continue to run in background while a foreground application will restore a usable screen and graphics mode in case of a crash. The forktest(6) demo shows the principal operation. (*shutdown_routine)() is called when the system crashes. However, realize that the call will take in a forked copy of your program, you'll not have access to any globals modified after the vga_safety_fork() call! SEE ALSO
svgalib(7), vgagl(7), libvga.config(5), forktest(6), vga_init(3), AUTHOR
This manual page was edited by Michael Weller <eowmob@exp-math.uni-essen.de>. The exact source of the referenced function as well as of the original documentation is unknown. It is very likely that both are at least to some extent are due to Harm Hanemaayer <H.Hanemaayer@inter.nl.net>. Occasionally this might be wrong. I hereby asked to be excused by the original author and will happily accept any additions or corrections to this first version of the svgalib manual. Svgalib (>;= 1.2.11) 27 July 1997 vga_safety_fork(3)
Check Out this Related Man Page
restoretextmode(1) Svgalib User Manual restoretextmode(1) NAME
restoretextmode - save or restore the SVGA registers for textmode. SYNOPSIS
restoretextmode {-r|-w} filename DESCRIPTION
The state of the SVGA is written to or restored from filename using the vga_gettextmoderegs(3) and vga_settextmoderegs(3) functions. As of this writing this file is 385 bytes long but this might change with future versions. Please do not fiddle with the contents of the file except when you know what you do. It might even result in hardware damage. Because of that, you should think twice to make this command available to all users on your system. The purpose of this program is usually to recover from a crashed console due to an svgalib, Xfree or other program bug. First save the state of the SVGA card when on a text console. After the crash restore this state. The savetextmode(1) and textmode(1) script makes this procedure very easy. OPTIONS
-w filename write the SVGA state to the file filename. -r filename restore the SVGA state from the file filename. SEE ALSO
svgalib(7), vgagl(7), libvga.config(5), vga_gettextmoderegs(3), vga_settextmoderegs(3), dumpreg(1), convfont(1), fix132x43(1), restore- font(1), restorepalette(1), runx(1), savetextmode(1), setmclk(1), textmode(1). AUTHOR
This manual page was edited by Michael Weller <eowmob@exp-math.uni-essen.de>. The exact source of the referenced utility as well as of the original documentation is unknown. It is very likely that both are at least to some extent are due to Harm Hanemaayer <H.Hanemaayer@inter.nl.net>. Occasionally this might be wrong. I hereby asked to be excused by the original author and will happily accept any additions or corrections to this first version of the svgalib manual. Svgalib (>;= 1.2.11) 2 Aug 1997 restoretextmode(1)