svn commit: r283088 - head/sys/ddb

[Garrett Cooper]

> On May 18, 2015, at 22:28, Pedro Giffuni <pfg at FreeBSD.org> wrote:
> 
> 
>> Il giorno 18/mag/2015, alle ore 23:34, Bruce Evans <brde at optusnet.com.au> ha scritto:
>> 
>> On Mon, 18 May 2015, Pedro Giffuni wrote:
>> 
>>>> Il giorno 18/mag/2015, alle ore 20:48, Bruce Evans <brde at optusnet.com.au> ha scritto:
>>>> 
>>>>> On Mon, 18 May 2015, Pedro F. Giffuni wrote:
>>>>> 
>>>>> Log:
>>>>> ddb: stop boolean screaming.
>>>>> 
>>>>> TRUE --> true
>>>>> FALSE--> false
>>>>> 
>>>>> Hinted by:	NetBSD
>>>> 
>>>> This is not just churn to a style regression, but a type mismatch.
>>> 
>>> It is an attempt to reduce differences with NetBSD.
>> 
>> For that, apply the reverse change to NetBSD.
> 
> Actually, the NetBSD code uses bool. (I hate CVS, commits are not atomic.)
> 
>>> One of the complaints of hear from newcomers to the ddb code is that
>>> the format is old-fashioned (it still had pre-ANSI headers not long ago)
>>> and unmaintained.
>> 
>> It is fairly well maintained (not churned to unimprove its portability).
>> Why would newcomers want too look at it?
> 
> Unrelated fun: last year a student started adding support for CTF and pretty printing of the kernel structures. I think the NetBSD guys have been having fun with Lua.
> 
> 
>>>>> Modified: head/sys/ddb/db_break.c
>>>>> ==============================================================================
>>>>> --- head/sys/ddb/db_break.c	Mon May 18 22:14:06 2015	(r283087)
>>>>> +++ head/sys/ddb/db_break.c	Mon May 18 22:27:46 2015	(r283088)
>>>>> @@ -155,12 +155,12 @@ db_find_breakpoint_here(db_addr_t addr)
>>>>> 	return db_find_breakpoint(db_map_addr(addr), addr);
>>>>> }
>>>>> 
>>>>> -static boolean_t	db_breakpoints_inserted = TRUE;
>>>>> +static boolean_t	db_breakpoints_inserted = true;
>>>> 
>>>> This code hasn't been churned to use the boolean type.  It still uses
>>>> boolean_t, which is plain int.  TRUE and FALSE go with this type.  true
>>>> and false go with the boolean type.  This probably makes no difference,
>>>> because TRUE happens to be implemented with the same value as true and
>>>> there are lots of implicit versions between the types.
>>> 
>>> Yes, I noticed the return types are still ints. It doesn’t look difficult
>>> to convert it to use a real boolean type.  In any case, I would prefer to go
>>> forward (using bool) instead of reverting this change.
>> 
>> That wuld be sideways.
>> 
>> I forgot to mention (again) in my previous reply that boolean_t is a mistake
>> by me.  KNF code doesn't even use the ! operator, but uses explicit
>> comparison with 0.  The boolean_t type and TRUE and FALSE are from Mach.
>> They were used mainly in ddb and vm, and are still almost never used in
>> kern.  I used to like typedefs and a typedef for boolean types, and didn't
>> know KNF very well, so in 1995 I moved the declaration of boolean_t from
>> Mach vm code to sys/types.h to try to popularize it.  This was a mistake.
>> Fortunately, it is still rarely used in core kernel code.
>> 
>> The boolean type is also almost never used for syscalls.  In POSIX.1-2001,
>> <stdbool.h> is inherited from C99, but is never used for any other POSIX
>> API.  Using it for syscalls would mainly cause portability problems.
> 
> OK, I do understand the kernel wants to keep the C dialect somewhat limited,
> and adding stdbool.h doesn’t buy us any type safety here.
> 
> I’ll revert the change (prob. tomorrow though).

Too bad. You could just convert bool to an enum, add a compile-time assert, and chase down all of the -Werrors with clang...

... Nevermind. Not fun :(..