Re: [Qemu-devel] [PATCH v2 00/16] arm: A9MPCore+A15MPCore QOM'ification

[Alexander Graf]

On 23.07.2013, at 23:52, Peter Maydell wrote:

> On 23 July 2013 22:36, Alexander Graf <address@hidden> wrote:
>> 
>> 
>> Am 23.07.2013 um 23:16 schrieb Peter Maydell <address@hidden>:
>> 
>>> On 23 July 2013 20:15, Peter Maydell <address@hidden> wrote:
>>>> I had a thought about this. Suppose we have our class header
>>>> files do something like this:
>>>> 
>>>> #ifdef MYCLASS_IMPLEMENTATION
>>>> #define PRIVATE
>>>> #else
>>>> #ifdef __GNUC__
>>>> #define PRIVATE __attribute__((deprecated("this is a private field")))
>>>> #else
>>>> #define PRIVATE
>>>> #endif
>>>> 
>>>> typedef struct MyObject {
>>>>  int publicfield;
>>>>  int privatefield PRIVATE;
>>>> } MyObject;
>>> 
>>> Forgot to say, but if people don't think this is an
>>> intrinsically terrible idea I'll put together a patch that
>>> does this sometime this week.
>> 
>> I like the idea, but could we make this slightly less upper case? Something 
>> like
>> 
>>  __private int privatefield;
>> 
>> feels more readable imho.
> 
> Well, __ is using the reserved namespace, but we could use something
> else, and it looks like gcc lets us put the attribute at the front.
> Since we'll want to undef whatever we pick after the struct is defined
> we can actually use pretty much anything without worrying about it
> stealing namespace.

Very nice :). And it aligns pretty well with the __user hint in Linux.

> (We could even use just 'private' if we didn't mind (a) not being
> able to compile with a C++ compiler and (b) confusing everybody
> completely :-))
> 
>> Or maybe
>> 
>> struct MyObject {
>>  PUBLIC_FIELDS
>>  __field int publicfield;
>>  PRIVATE_FIELDS
>>  __field int privatefield;
>> }
> 
> I can't see an obvious way to make those do the right
> thing with the C preprocessor... am I missing something?

No, I'm probably just daydreaming :). Macros can't redefine other defines, so 
this probably won't work....

So yes, prepending the visibility on every field seems to be the most straight 
forward choice.


Alex