vga_safety_fork - start a parallel process to restore the console at a crash
void vga_safety_fork(void (*shutdown_routine)(void))
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 drivers 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()
already enter a graphicsmode. (For font and grafix state saving). Don't
overestimate the power of this function. 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.
(6) demo shows the principal operation.
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
This manual page was edited by Michael Weller
<email@example.com>. 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
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.