vm86(2) — Linux manual page

NAME \| LIBRARY \| SYNOPSIS \| DESCRIPTION \| RETURN VALUE \| ERRORS \| STANDARDS \| COLOPHON

vm86(2)                    System Calls Manual                    vm86(2)

NAME top

       vm86old, vm86 - enter virtual 8086 mode

LIBRARY top

       Standard C library (libc, -lc)

SYNOPSIS top

       #include <sys/vm86.h>

       int vm86old(struct vm86_struct *info);
       int vm86(unsigned long fn, struct vm86plus_struct *v86);

DESCRIPTION top

       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 top

       On success, zero is returned.  On error, -1 is returned, and errno
       is set to indicate the error.

ERRORS top

       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 top

       Linux on 32-bit Intel processors.

COLOPHON top

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Linux man-pages 6.15            2025-05-17                        vm86(2)

Pages that refer to this page: modify_ldt(2), syscalls(2), unimplemented(2), systemd.exec(5)