vm86(2)                       System Calls Manual                      vm86(2)

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
       Linux on 32-bit Intel processors.

Linux man-pages 6.7               2023-10-31                           vm86(2)