转贴 C++ Coding Standards

C++ Coding Standards


$Organizational and Policy Issues

0. Don’t sweat the small stuff. (Or: Know what not to standardize.) 2

1. Compile cleanly at high warning levels. 4

2. Use an automated build system. 7

3. Use a version control system. 8

4. Invest in code reviews. 9

$Design Style

5. Give one entity one cohesive responsibility. 12

6. Correctness, simplicity, and clarity come first. 13

7. Know when and how to code for scalability. 14

8. Don’t optimize prematurely. 16

9. Don’t pessimize prematurely. 18

10. Minimize global and shared data. 19

11. Hide information. 20

12. Know when and how to code for concurrency. 21

13. Ensure resources are owned by objects. Use explicit RAII and smart pointers. 24

$Coding Style

14. Prefer compile- and link-time errors to run-time errors. 28

15. Use const proactively. 30

16. Avoid macros. 32

17. Avoid magic numbers. 34

18. Declare variables as locally as possible. 35

19. Always initialize variables. 36

20. Avoid long functions. Avoid deep nesting. 38

21. Avoid initialization dependencies across compilation units. 39

22. Minimize definitional dependencies. Avoid cyclic dependencies. 40

23. Make header files self-sufficient. 42

24. Always write internal #include guards. Never write external #include guards. 43

$Functions and Operators

25. Take parameters appropriately by value, (smart) pointer, or reference. 46

26. Preserve natural semantics for overloaded operators. 47

27. Prefer the canonical forms of arithmetic and assignment operators. 48

28. Prefer the canonical form of ++ and --. Prefer calling the prefix forms. 50

29. Consider overloading to avoid implicit type conversions. 51

30. Avoid overloading &&, ||, or , (comma) . 52

31. Don’t write code that depends on the order of evaluation of function arguments. 54

$Class Design and Inheritance

32. Be clear what kind of class you’re writing. 56

33. Prefer minimal classes to monolithic classes. 57

34. Prefer composition to inheritance. 58

35. Avoid inheriting from classes that were not designed to be base classes. 60

36. Prefer providing abstract interfaces. 62

37. Public inheritance is substitutability. Inherit, not to reuse, but to be reused. 64

38. Practice safe overriding. 66

39. Consider making virtual functions nonpublic, and public functions nonvirtual. 68

40. Avoid providing implicit conversions. 70

41. Make data members private, except in behaviorless aggregates (C-style structs). 72

42. Don’t give away your internals. 74

43. Pimpl judiciously. 76

44. Prefer writing nonmember nonfriend functions. 79

45. Always provide new and delete together. 80

46. If you provide any class-specific new, provide all of the standard forms (plain, in-place, and nothrow). 82

$Construction, Destruction, and Copying

47. Define and initialize member variables in the same order. 86

48. Prefer initialization to assignment in constructors. 87

49. Avoid calling virtual functions in constructors and destructors. 88

50. Make base class destructors public and virtual, or protected and nonvirtual. 90

51. Destructors, deallocation, and swap never fail. 92

52. Copy and destroy consistently. 94

53. Explicitly enable or disable copying. 95

54. Avoid slicing. Consider Clone instead of copying in base classes. 96

55. Prefer the canonical form of assignment. 99

56. Whenever it makes sense, provide a no-fail swap (and provide it correctly). 100

$Namespaces and Modules

57. Keep a type and its nonmember function interface in the same namespace. 104

58. Keep types and functions in separate namespaces unless they’re specifically intended to work together. 106

59. Don’t write namespace usings in a header file or before an #include. 108

60. Avoid allocating and deallocating memory in different modules. 111

61. Don’t define entities with linkage in a header file. 112

62. Don’t allow exceptions to propagate across module boundaries. 114

63. Use sufficiently portable types in a module’s interface. 116

$Templates and Genericity

64. Blend static and dynamic polymorphism judiciously. 120

65. Customize intentionally and explicitly. 122

66. Don’t specialize function templates. 126

67. Don’t write unintentionally nongeneric code. 128

$Error Handling and Exceptions

68. Assert liberally to document internal assumptions and invariants. 130

69. Establish a rational error handling policy, and follow it strictly. 132

70. Distinguish between errors and non-errors. 134

71. Design and write error-safe code. 137

72. Prefer to use exceptions to report errors. 140

73. Throw by value, catch by reference. 144

74. Report, handle, and translate errors appropriately. 145

75. Avoid exception specifications. 146

$STL: Containers

76. Use vector by default. Otherwise, choose an appropriate container. 150

77. Use vector and string instead of arrays. 152

78. Use vector (and string::c_str) to exchange data with non-C++ APIs. 153

79. Store only values and smart pointers in containers. 154

80. Prefer push_back to other ways of expanding a sequence. 155

81. Prefer range operations to single-element operations. 156

82. Use the accepted idioms to really shrink capacity and really erase elements. 157

$STL: Algorithms

83. Use a checked STL implementation. 160

84. Prefer algorithm calls to handwritten loops. 162

85. Use the right STL search algorithm. 165

86. Use the right STL sort algorithm. 166

87. Make predicates pure functions. 168

88. Prefer function objects over functions as algorithm and comparer arguments. 170

89. Write function objects correctly. 172

$Type Safety

90. Avoid type switching; prefer polymorphism. 174

91. Rely on types, not on representations. 176

92. Avoid using reinterpret_cast. 177

93. Avoid using static_cast on pointers. 178

94. Avoid casting away const. 179

95. Don’t use C-style casts. 180

96. Don’t memcpy or memcmp non-PODs. 182

97. Don’t use unions to reinterpret representation. 183

98. Don’t use varargs (ellipsis). 184

99. Don’t use invalid objects. Don’t use unsafe functions. 185

100. Don’t treat arrays polymorphically. 186