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1Every project has its coding style, and kmod is not an exception. This
2document describes the preferred coding style for kmod code, in order to keep
3some level of consistency among developers so that code can be easily
4understood and maintained, and also to help your code survive under
5maintainer's fastidious eyes so that you can get a passport for your patch
6ASAP.
7
8First of all, kmod coding style must follow every rule for Linux kernel
9(http://www.kernel.org/doc/Documentation/CodingStyle). There also exists a tool
10named checkpatch.pl to help you check the compliance with it. Just type
11"checkpatch.pl --no-tree patch_name" to check your patch. In theory, you need
12to clean up all the warnings and errors except this one: "ERROR: Missing
13Signed-off-by: line(s)". kmod does not used Signed-Off lines, so including
14them is actually an error.  In certain circumstances one can ignore the 80
15character per line limit.  This is generally only allowed if the alternative
16would make the code even less readable.
17
18Besides the kernel coding style above, kmod coding style is heavily based on
19oFono's and BlueZ's. Below some basic rules:
20
211) Wrap line at 80 char limit.
22
23There are a few exceptions:
24	- Headers may or may not wrap
25	- If it's a string that is hitting the limit, it's preferred not to break
26	  in order to be able to grep for that string. E.g:
27
28		err = my_function(ctx, "this is a long string that will pass the 80chr limit");
29
30	- If code would become unreadable if line is wrapped
31	- If there's only one argument to the function, don't put it alone in a
32	  new line.
33
34Align the wrapped line either with tabs (BlueZ, oFono, etc) or tab + spaces
35(kernel), at your discretion. Kernel's is preferred.
36
372) It's better to return/exit early in a function than having a really long
38   "if (...) { }". Example:
39
40   if (x) {	// worse	|	if (!x)			// better
41	   ...			|		return b;
42	   ...			|
43	   ...			|	...
44	   ...			|	...
45	   ...			|	...
46	   ...			|	...
47	   ...			|	...
48	   ...			|	...
49   } else {			|	...
50	   return b;		|	return a;
51   }				|
52				|
53   return a;			|
54
553) Don't initialize variable unnecessarily
56When declaring a variable, try not to initialize it unless necessary.
57
58Example:
59int i = 1;  // wrong
60
61for (i = 0; i < 3; i++) {
62}
63
644) Let the includes in the following order, separated by a new line:
65	< system headers >
66	< shared/* >
67	< libkmod >
68	< tool >
69	"local headers"
70