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 3.23 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.
