Re: [KJ] standardizing on boolean variables?

[Richard Knutsson <ricknu-0@student.ltu.se>]

Robert P. J. Day wrote:
> On Sun, 21 Jan 2007, Alexey Dobriyan wrote:
>
>   
>> On Sun, Jan 21, 2007 at 03:36:33AM -0500, Robert P. J. Day wrote:
>>     
>>> p.s.  the source file drivers/scsi/BusLogic.c repeatedly refers to the
>>> token "true", but it's not clear where *that's" being defined.  goes
>>> gcc actually recognize the token "true"?  that's supposed to be
>>> defined in C99's <stdbool.h>, but that's clearly not being used here.
>>>       
>> When in doubt see preprocessor output:
>>
>> 	make drivers/scsi/BusLogic.i
>>
>> 	# 1 "/home/linux/linux-irq-flags-t/include/linux/stddef.h" 1
>> 	# 15 "/home/linux/linux-irq-flags-t/include/linux/stddef.h"
>> 	enum {
>> 	 false = 0,
>> 	 true = 1
>> 	};
>>
>> Indeed, "true" is right there.
>>     
>
> ah, quite right, i missed that.  but that, of course, just raises
> another question -- why have two different sets of tokens representing
> boolean values?  should programmers use the upper or lower case form?
> and why did the person who wrote BusLogic.c do it differently from
> everyone else?  so many pedantic, anal-retentive questions.
>   
Simple, some people defines 'FALSE'/'TRUE' and some 'false'/'true' ;)
Then, to be able to compile, the 
"6e21828743247270d09a86756a0c11702500dbfb" (git show) redefined BusLogic.h's

-typedef enum { false, true } __attribute__ ((packed)) boolean;

to

+typedef bool boolean;

Also, NTFS has been converted and some more filesystems.
> but back to the question at hand -- is there any fundamental problem
> with trying to define a standard by defining TRUE and FALSE macros in
> types.h?  certainly, that would also require some simultaneous fixes
> to the source tree, where those new macros would clash with existing
> code, like in drivers/net/wireless/strip.c, where one would have to
> remove the conflicting:
>
>   enum { FALSE = 0, TRUE = 1 };
>
> but i'm guessing things like that would be rare.
>   
Please, try to convert it to 'false'/'true' instead. It is meant to be 
the generic boolean-values, same as bool being the type.
Believe it is approved since I saw a patch, adding a function using bool 
and 'false'/'true', signed-off-by Torvalds and Morton (not sure it was a 
third name).

I have not got too much done in the converting-front (some wants it 
changed to int/0/1 instead); maybe this is something to add on Wiki- ToDo :)

Richard Knutsson

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