[PATCH] docs: point out that locals should be defined at the top of a block of code

[Andrea Bolognani]

On Thu, 2020-07-09 at 18:41 -0400, Laine Stump wrote:
> +Defining Local Variables
> +------------------------
> +
> +Always define local variables at the top of the block in which they
> +are used (before any pure code). Although modern C compilers allow
> +defining a local variable in the middle of a block of code, this
> +practice can lead to bugs, and must be avoided in all libvirt
> +code. (As indicated in these examples, it is okay to initialize
> +variables where they are defined, even if the initialization involves
> +calling another function.)

The parentheses around the last sentence are unnecessary, please
drop them.

> +  GOOD:
> +    int
> +    Bob(char *loblaw)
> +    {
> +        int x;
> +        int y = lawBlog(loblaw);

I believe this should be

  int y = lawBlog();

but note that I haven't compile-tested this alternative version.

> +  BAD:
> +    int
> +    Bob(char *loblaw)
> +    {
> +        int x;
> +        int y = lawBlog(loblaw);
> +
> +        x = y + 20;
> +
> +        char *z = NULL; <===

Please add // in front of the ASCII arrow.

It's pretty weird how we use C++-style comments throughout our style
guide, at the same time as *the style guide itself* instructs
developers to use C-style comments instead, but addressing that is a
job for another patch :)


With the nits fixed,

  Reviewed-by: Andrea Bolognani <abologna at redhat.com>

-- 
Andrea Bolognani / Red Hat / Virtualization