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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 Intel processors, and should not be
       used in programs intended to be portable.

COLOPHON

       This page is part of release 2.77 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/.