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vm86 (2)
VM86(2) Linux Programmer's Manual VM86(2)
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 intro-
duced. 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 Intel processors, and should not be
used in programs intended to be portable.
Linux 1997-07-17 VM86(2)
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