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)