Subject: Re: CVS commit: src/sys/sys
To: Hubert Feyrer <>
From: Jason Thorpe <>
List: source-changes
Date: 12/20/2005 08:09:32
On Dec 19, 2005, at 10:01 PM, Hubert Feyrer wrote:

> On Tue, 20 Dec 2005, YAMAMOTO Takashi wrote:
>>> This is probably a very stupid question, but... what I wonder is  
>>> how to
>>> get a "struct device foodev" that way,
>> you can't.  you don't need to do so, if you make it really opaque.
> What does "opaque" mean? I wonder where all those things come from  
> that these pointers point to... X-)

"opaque" means you can't see into it.  You don't know, or care, if  
it's an int, a pointer, a float, whatever.

> (Yes, I'm aware that this is a very newbie question... I fetched  
> myself a bloody nose again trying to dig into our kernel, and still  
> have no real idea where to start; I'm aware that this is probably  
> not the best point?)

Opaque types are hardly limited to the kernel.  pthread_t is an  
opaque type, for example.

-- thorpej