Autobahn C Coding Standards

[ericchapman]

@oberstat So after googling it, there is no real globally used standard for C code. Every company, college, etc. seem to have invented their own. That being said, here are the two that come to mind

• Linux Kernel (https://www.kernel.org/doc/Documentation/CodingStyle)
• GNU (https://www.gnu.org/prep/standards/html_node/Formatting.html#Formatting)

The GNU one is short and sweet while the Linux one seems to be more concise AND give reasons for why things are a bad idea. I am leaning towards Linux but open for suggestions.

[oberstet]

I dislike the GNU style. The Linux one is nicer. This is mostly K&R - which I do like.

How about this: https://www.nginx.com/resources/wiki/start/topics/examples/coding_style/

It's also K&R, but uses 4 spaces per indent.

Nginx is a modern C code base written by cracks .. scanning through some sources https://github.com/nginx/nginx/tree/master/src .. I like it. I immediately feel comfortable with this.

They seem to have the habit of placing return type and function on different lines though https://github.com/nginx/nginx/blob/master/src/event/ngx_event_accept.c#L22

Looking at RIOT OS, they do place everything on one line https://github.com/RIOT-OS/RIOT/blob/master/core/msg.c#L281

RIOT is also K&R, 4 spaces. Their style guide is here: https://github.com/RIOT-OS/RIOT/wiki/Coding-conventions.

In fact, scanning over RIOT: very clean code. Immediately readable.

void bloom_del(bloom_t *bloom)
{
...
}

I have the habit of writing this

void bloom_del (bloom_t* bloom)
{
...
}

2 spaces places differently. And the have no space only in invocation:

bloom_del(p);

I've also had a quick look at Apache and Mozilla guides .. less nice to my eyes.

Following the RIOT guide would have an additional benefit, as RIOT is the primary incubator for AutobahnC - so we are immediately "on track".

[ericchapman]

@oberstet Yes!! I like the RIOT one. Definitely how I naturally code as well in C. I am in agreement with that if you want to make it official. I also like the "type_t" notation which the Linux one didn't seem to like. It feels more natural in a C world.

Do we want Autobahn C types to have a prefix to avoid possible collisions or just leave it? For example

typedef struct session_s {
    ...
} session_t;

vs.

typedef struct ab_session_s {
    ...
} ab_session_t;

I think the non-prefixed type looks cleaner.

[oberstet]

Agreed to all! Lets follow the RIOT coding guide. And no prefixes. So I guess we can close this. I will write a CONTRIBUTING.md that persists our decision.