netbsd man page for i386_iopl

I386_IOPL(2)						   BSD/i386 System Calls Manual 					      I386_IOPL(2)

NAME
     i386_iopl -- change the i386 I/O privilege level

LIBRARY
     i386 Architecture Library (libi386, -li386)

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.

BSD
								  April 12, 2004							       BSD