Coding Style
先看 [http://lxr.linux.no/source/Documentation/CodingStyle Linux kernel coding style]
Indentation
- 8-char indent
- If you need more than 3 levels of indentation, you're screwed anyway, and should fix your program.
- Don't put multiple statements on a single line unless you have something to hide.
- Get a decent editor, and don't leave whitespace at the end of lines.
Breaking long lines and strings
- Coding style is all about readability and maintainabilty using commonly avaible tools.
- The limit on the length of lines is 80 colums and this is a hard limit.
Placing braces
- The preferred way, as shown to us by the prophets Kernighan and Ritchie, is to put the opening brace last on the line, and put the closing brace first.
- namely function have the opening brace at the begining of the next line.
Naming
- C is a Spartan language, and so should your naming be.
- GLOBAL variables (to be used only if you _really_need them) need to have descriptive name, as do global functions.
- LOCAL variable name should be short, and to the point.
Fuctions
- Fuctions should be short and sweet, and do just one thind.
- Another measure of the functions is the number of local variables, They shouldn't exceed 5-10, or you're doing something wrong.
Centralized exiting of functions
- About gogo statement.
Commenting
- Comments are good, but there is also a demage of over-commenting.
- Generally, you want your comments to tell WHAT your code does, not HOW.
You've made a mess of it
- About GNU Emacs and GNU indent.
- 'indent' is not a fix for bad programing.
Data structures
- Data structures that have visibility outside the single-threaded environment they are created and destoryed in should always have reference counts.
- Locking is _not_ a replacement for reference counting.
- If another thread can find your data structure, and you don't have a reference count on it, you almost certainly have a bug.
Macros, Enums, Inline functions and RTL
- Names of macros defining contants and labels in enums are capitalized.
- Enums are preferred when defining serval related constants.
- Generally, inline functions are preferable to macros resembling functions.
- Macros with multiple statements should be enclosed in a do-while block.
malloc, calloc, free
- 一个严重的错误：释放不是通过调用 malloc, calloc 得到的指针所指向的存储空间。
- 使用已释放空间同样是错误的。