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
user-space 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 exist only within vm86 mode itself.)
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 3.74 of the Linux
man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at
http://www.kernel.org/doc/man-pages/.
