Coding Convention

Comment

Linux kernel comment (most case, ther is no hard rule):

Start with a uppercase letter.
Not to end imperative sentences with a period.
End the first sentence with a period if multiple sentences.
Not to use third-person singular form for the beginning verb.
TODO starts with // TODO(yaojingguo@gmail.com): . The following sentence should begin with a uppercase letter.

Golang:

Start with function name.
Always end with a period.

I follow the Linux kernel way.

Logging

Linux Kernel:

Start with a uppercase letter.
Not to end imperative sentences with a period.
Not to use third-person singular form for the beginning verb.

cockroachDB: Start with a letter case letter unless the raw word is capitalised.

Imperative form for some short-duration thing to happen.

drop schema change mutation: %+v
begin sampling phase of job %s
drop index (%d, %d) at row: %d, span:

Present continuous tense for for some long-duration thing to happen. is is omitted. If the subject is the running system itself, omit subject.

pushing expired txn %s
planner acquiring lease on table '%s'
cleaning up bootstrap addresses
not seeking (key=%s); existing descriptor %s
pgwire writing TEXT datum of type: %T, %#v

Passive form for something happed in the past. is is omitted.

optimizer disabled
outbox flushed
node label %s not found
table %d version %d not found

Past tense for some thing happened in the past. If the subject is the running system itself, omit subject.

found uncommitted table %d
added table '%s' to table collection
failed to read gossip bootstrap info: %s
not pushed; returning to caller
found new resolvers from storage; signaling bootstrap
didn't insert all buffered rows and yet no error was reported.
failed to create config data dir %v
Inbox reader arrived

The first word of a single sentence is not capitalized.

ranges are not adjacent; %s != %s

error doing something form

error setting up client session: %v

Print

If Print is used as logging, follow logging convention. Otherwise, starts with a uppercase letter.

Hexadecimal

CSAPP convention:

Use ‘0x’ prefix.
Use uppercase letters for A-F.

hello code

The hello.c from K&R:

#include <stdio.h>

main()
{
    printf("hello, world\n");
}

Prefix

If a package name is use as prefix for a logging message or commit message subject line, it is used without any conversion.

References

Linux kernel coding style

Mail

For the line width, there is no hard rule for linux kernel mail list.

Linus:

Linux 4.19-rc4 released, an apology, and a maintainership note

having screwed up my calendar, but honestly, I was mostly hopeful that
I

>>> len("having screwed up my calendar, but honestly, I was mostly hopeful that")
70

Width is at most 72.

Re: Availability of kdb

>>> len("sources. At the meaning of things. Without a debugger, you basically have")
73

of reactions to that: you start being careful, or you start whining about
a kernel debugger.

>>> len("of reactions to that: you start being careful, or you start whining about")
73

Re: [BREAKAGE] Since 4.18, kernel sets SB_I_NODEV implicitly on userns mounts, breaking systemd-nspawn
```
>>> len("The fact that you tried to several times claim it was buggy user space")
70
```

G-H:

Re: The most insane proposal in regard to the Linux kernel development share

>>> len("operating system's drivers _because_ of our development model.  You wish")
72

https://news.ycombinator.com/item?id=7994190

Many plaintext clients default to 72 to allow room for multiple levels of quoting.

http://kb.mozillazine.org/Plain_text_e-mail_-_Thunderbird says:

You can use mailnews.wraplength to change the line length for messages you compose (defaults to 72 characters), mail.compose.wrap_to_window_width to wrap to the window width when composing a message (defaults to false) and mail.wrap_long_lines to control the wrapping of long lines (defaults to true).

I use 72 for line width.

Wrap effect of LKML web page: https://lkml.org/lkml/2019/5/20/1845