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.)

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 3.54 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/.