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VM86

Section: Linux Programmer's Manual (2)
Updated: 2009-02-20
Index Return to Main Contents

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NAME

vm86old, vm86 - enter virtual 8086 mode  

SYNOPSIS

#include <sys/vm86.h>

int vm86old(struct vm86_struct *info);

int vm86(unsigned long fn, struct vm86plus_struct *v86);  

DESCRIPTION

The system call vm86() was introduced in Linux 0.97p2. In Linux 2.1.15 and 2.0.28 it was renamed to vm86old(), and a new vm86() was introduced. The definition of struct vm86_struct was changed in 1.1.8 and 1.1.9.

These calls cause the process to enter VM86 mode (virtual-8086 in Intel literature), and are used by dosemu.

VM86 mode is an emulation of real mode within a protected mode task.  

RETURN VALUE

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.  

ERRORS

EFAULT

This return value is specific to i386 and indicates a problem with getting userspace data.

ENOSYS

This return value indicates the call is not implemented on the present architecture.

EPERM

Saved kernel stack exists. (This is a kernel sanity check; the saved stack should only exist within vm86 mode itself.)

 

CONFORMING TO

This call is specific to Linux on 32-bit Intel processors, and should not be used in programs intended to be portable.  

COLOPHON

This page is part of release 3.35 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://man7.org/linux/man-pages/.

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Index

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

CONFORMING TO

COLOPHON

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