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vm86(2) — Linux manual page

vm86(2)                    System Calls Manualvm86(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 longfn, struct vm86plus_struct *v86);

DESCRIPTION        top

       The system callvm86() was introduced in Linux 0.97p2.  In Linux       2.1.15 and 2.0.28, it was renamed tovm86old(), and a newvm86()       was introduced.  The definition ofstruct 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 bydosemu.       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, anderrno       is set to indicate the error.

ERRORS        top

EFAULTThis return value is specific to i386 and indicates a              problem with getting user-space data.ENOSYSThis return value indicates the call is not implemented on              the present architecture.EPERMSaved 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

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17vm86(2)

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

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