NAME

       vm86old, vm86 - enter virtual 8086 mode

LIBRARY

       Standard C library (libc, -lc)

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 to indicate  the
       error.

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.)

STANDARDS

       This call is specific to Linux on 32-bit Intel processors,  and  should  not  be  used  in
       programs intended to be portable.