Re: libmachuser vs libmach

[James Morrison]

--- "Thomas Bushnell, BSG" <tb@becket.net> wrote:
> James Morrison <rocketmail_com@rocketmail.com> writes:
> 
> > I've been looking though some of the mach interfaces and libmach
> > is mentioned in a few places.  This looks to be libmachuser for us,
> > is this correct?
> 
> libmach existed in some old CMU systems.  It included libmachuser, as
> well as some additional user-space-only functions.  (The CMU systems
> had a libmachuser which was, more or less, just like ours.)
 
 A nice tidbit to add to the Mach manual.

> > I'm also curious about the machine_slot_data_t type, the comment
> > says it is bogus, but the interface for xxx_slot_info uses
> > machine_slot_data_t instead of machien_slot_t, should this be fixed?
> > Also is there any reason that the function to get the function to
> > get more information about a processor is prefixed with xxx?
> 
> xxx means that it's deprecated or otherwise discouraged.  The fact
> that machine_slot_data_t is used only in xxx_slot_info is precisely
> why you should believe that it's bogus.
> 
> The reason the type is discouraged is that returning a straightforward
> struct is a bad idea.  (Compare xxx_host_info with the current
> host_info RPC.)  So there should be a revamped slot_info function too,
> (and cpu_control) though that hasn't been done yet.
> 
> Thomas
> 

 Ok, I'm not too sure what is going on with host_info and xxx_host_info, but it
seems that xxx_host_info is call to the kernel without using mig, but host_info
is an interface created by mig.  So with host_info the struct is copied to the
user process, where in xxx_host_info the struct is simply given to the user
process.  Am I understanding any of this?


=====
James Morrison
   University of Waterloo
   Computer Science - Digital Hardware
   2A co-op
http://hurd.dyndns.org

Anyone referring to this as 'Open Source' shall be eaten by a GNU

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