Re: kernel guide to space

[Horst von Brand <vonbrand@inf.utfsm.cl>]

Jesper Juhl <jesper.juhl@gmail.com> wrote:
> On 7/11/05, Michael S. Tsirkin <mst@mellanox.co.il> wrote:

> [snip]

> > 3e. sizeof
> >         space after the operator
> >         sizeof a

> I don't think that's a hard rule, there's plenty of code that does 
> "sizeof(type)"  and not  "sizeof (type)", and whitespace cleanup
> patches I've done that change "sizeof (type)" into "sizeof(type)" have
> generally been accepted.

It is necessary /not/ to put space between "function name" and '(', because
if it is a function-like macro, it does matter. For uniformity, do it for
functions and operations like sizeof too.

> [snip]
> > 
> > 4. Indentation rules for C
> >         Use tabs, not spaces, for indentation. Tabs should be 8 characters wide.

> A tab is a tab is a tab, how it's displayed is up to the editor
> showing the file.

But editing a file with tab==4 and editing it later with tab==8 guarantees
a mess.

[...]

> > 6. One-line statement does not need a {} block, so dont put it into one
> >         if (foo)
> >                 bar;

> Not always so, if `bar' is a macro adding {} may be safer.

Such macros are /very/ dangerous. That's one reason why multi-line macros
must be wrapped in "do { ... } while(0)"

>                                                            Also
> sometimes adding {} improves readability, which is important.

Or leaves an old C hand wondering what is going on...

> > 7. Comments
> >         Dont use C99 // comments.
> > 
> 
> s/Dont/Don't/
> 
> 
> > 9a. Integer types
> >         int is the default integer type.
> >         Use unsigned type if you perform bit operations (<<,>>,&,|,~).
> >         Use unsigned long if you have to fit a pointer into integer.
> >         long long is at least 64 bit wide on all platforms.
> >         char is for ASCII characters and strings.
> >         Use u8,u16,u32,u64 if you need an integer of a specific size.
> 
> u8,s8,u16,s16,u32,s32,u64,s64

Plus annotations for bitwise and such. See Documentation/sparse.txt
-- 
Dr. Horst H. von Brand                   User #22616 counter.li.org
Departamento de Informatica                     Fono: +56 32 654431
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