[U-Boot] use of C99

Timur Tabi
2009-04-08T20:25:27Z

On Wed, Apr 8, 2009 at 2:46 PM, Jerry Van Baren <gerald.vanbaren@ge.com> wrote:

> ACK. ?I don't expect to see variables spring into life in the middle of
> nowhere.

I don't see what's wrong with that. The advantage is that the
variable is close to where it's being used, so that you can see the
context more easily.

> If I'm not confused, I've seen block-local u-boot variables, has the
> advantages of being more distinctive and limits the lifetime of the
> variable.

I don't see what the value is of limiting the lifetime of the
variable. The compiler isn't going to use that as a hint, anyway.
It's just going to use this for syntax checking. If you define and
initialize a variable at the top of the function, but don't use that
variable until a hundred lines later, the compiler is going to
initialize the variable when it's first used, not when the function is
first entered. Chances are it's not even going to define stack space
for it.

> #ifdef CONFIG_COOL_FEATURE
> ? ? ? ?{
> ? ? ? ? ? ? ? ?u32 myvarrocks = foo * bar * bar;
>
> ? ? ? ? ? ? ? ?gd->neato = myvarrocks
> ? ? ? ?}
> #endif
>
> Is this an acceptable compromise?

This is what we do today, and I think it's ugly.

--
Timur Tabi
Linux kernel developer at Freescale