coding_style.md

Coding Style

This document refers to Linux kernel coding style, and is building in progress.

Formatting

1. Header files should be protected by #ifndef FILENAME_H clauses.
2. All files should be aligned by tab rather than space, tab size is 8.
3. In #define clauses, seperate #define and name with 1 space, name with value (if exist) with tab(s), nearby values should be vertically aligned by tab.
4. Define local variables inside function on their first usage; while defining multiple local variables at once, each variable takes 1 line, variable names should be aligned by tab.
5. Several common local variable names: i, j, k as enumerating variables, they should be defined inside for loop; r as result in clauses like if ((r = func()) < 0); tmp as temporary variable.
6. Only use typedef with a clear reason, refer to Linux kernel coding style. All typedef-ed name should end with _t, to distinguish from variable names.

Naming

1. Use {i|u}{8|16|32|64} as integer type name if size is important.
2. Global names should be descriptive, and identifiable between multiple context, e.g. CMD is a bad name.
3. Local names could be short, while not meaningless.
4. All names are in lower case and divided by underscore, except for constants, which should be in upper case and divided by underscore. As we don't use typedef heavily to redefine struct-s, all struct appears with the struct keyword, we can distinguish struct and variables according to this.
5. Define multiple relative constants in an enum{} is preferred.

OS-specific

1. All error codes should be defined inside errno.h by a enum, and corresponding error message defined in errno.c.