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 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 3.25 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/.



Linux                                                      2009-02-20                                                    VM86(2)