i386_iopl(2) - NetBSD Manual Pages

Command: Section: Arch: Collection:  
I386_IOPL(2)            NetBSD/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. NetBSD 9.0 April 12, 2004 NetBSD 9.0
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