NAME    [Toc]    [Back]

     i386_iopl - change the i386 I/O privilege level

LIBRARY    [Toc]    [Back]

     i386 Architecture Library (libi386, -li386)

SYNOPSIS    [Toc]    [Back]

     #include <sys/types.h>
     #include <machine/sysarch.h>

     int
     i386_iopl(int iopl);

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     i386_iopl() will fail if:

     [EPERM]   The caller was not the super-user, or the operation was not
               permitted at the current security level.

SEE ALSO    [Toc]    [Back]

     i386_get_ioperm(2), i386_set_ioperm(2)

REFERENCES    [Toc]    [Back]

     i386 Microprocessor Programmer's Reference Manual, Intel

WARNING    [Toc]    [Back]

     You can really hose your machine if you enable user-level I/O and write
     to hardware ports without care.

BSD                            October 14, 1995                            BSD