57 lines
1.8 KiB
Groff
57 lines
1.8 KiB
Groff
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.TH vga_safety_fork 3 "27 July 1997" "Svgalib (>= 1.2.11)" "Svgalib User Manual"
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.SH NAME
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vga_safety_fork \- start a parallel process to restore the console at a crash
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.SH SYNOPSIS
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.B "#include <vga.h>"
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.BI "void vga_safety_fork(void (*" shutdown_routine ")(void))"
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.SH DESCRIPTION
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Calling this at the start of a program results in a better
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chance of textmode being restored in case of a crash.
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However it has to raise the iopl level to 3 to work. This is
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a small security breach as it is inherited to any programs
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you fork of. However, some SVGA card drivers have to use
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iopl(3) anyway.
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If you use it call that function as the very first
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.B vga_
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function. Call it right before
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.B vga_init (3).
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Note that
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.B vga_safety_fork()
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will already enter a graphicsmode. (For font
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and grafix state saving).
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Don't overestimate the power of this function. Your application will continue to run
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in background while a foreground application will restore a usable screen and graphics
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mode in case of a crash.
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The
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.BR forktest (6)
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demo shows the principal operation.
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.BI (* shutdown_routine )()
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is called when the system crashes. However, realize that the call will take in a forked
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copy of your program, you'll not have access to any globals modified after the
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.B vga_safety_fork()
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call!
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.SH SEE ALSO
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.BR svgalib (7),
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.BR vgagl (7),
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.BR libvga.config (5),
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.BR forktest (6),
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.BR vga_init (3),
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.SH AUTHOR
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This manual page was edited by Michael Weller <eowmob@exp-math.uni-essen.de>. The
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exact source of the referenced function as well as of the original documentation is
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unknown.
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It is very likely that both are at least to some extent are due to
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Harm Hanemaayer <H.Hanemaayer@inter.nl.net>.
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Occasionally this might be wrong. I hereby
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asked to be excused by the original author and will happily accept any additions or corrections
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to this first version of the svgalib manual.
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