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Command: x86_64_iopl | Section: 2 | Source: NetBSD | File: x86_64_iopl.2
X86_64_IOPL(2) FreeBSD System Calls Manual (x86_64) X86_64_IOPL(2)
NAME
x86_64_iopl - change the x86_64 I/O privilege level
LIBRARY
x86_64 Architecture Library (libx86_64, -lx86_64)
SYNOPSIS
#include <sys/types.h>
#include <machine/sysarch.h>
int
x86_64_iopl(int iopl);
DESCRIPTION
x86_64_iopl() sets the x86_64 I/O privilege level to the value specified
by iopl. This call is restricted to the super-user.
RETURN VALUES
Upon successful completion, x86_64_iopl() returns 0. Otherwise, a value
of -1 is returned and the global variable errno is set to indicate the
error.
ERRORS
x86_64_iopl() will fail if:
[EPERM] The caller was not the super-user, or the operation was not
permitted at the current security level.
WARNING
You can really hose your machine if you enable user-level I/O and write
to hardware ports without care.
FreeBSD 14.1-RELEASE-p8 July 3, 2002 FreeBSD 14.1-RELEASE-p8