NAME
i386_iopl —
change the i386 I/O privilege
level
LIBRARY
library “libi386”
SYNOPSIS
#include
<sys/types.h>
#include
<machine/sysarch.h>
int
i386_iopl(int
iopl);
DESCRIPTION
i386_iopl()
sets the i386 I/O privilege level to the value specified by
iopl. This call is restricted to the super-user.
RETURN VALUES
Upon successful completion, i386_iopl()
returns 0. Otherwise, a value of -1 is returned and the global variable
errno is set to indicate the error.
ERRORS
i386_iopl() will fail if:
- [
EPERM] - The caller was not the super-user, or the operation was not permitted at the current security level.
REFERENCES
i386 Microprocessor Programmer's Reference Manual, Intel
WARNING
You can really hose your machine if you enable user-level I/O and write to hardware ports without care.