3.3 Macros and code sanity

• Preprocessor macro names MUST be entirely capitalized.
• As a general rule, preprocessor macro calls SHOULD NOT break code structure. Further specification of this point is given below.
• Macro call SHOULD NOT appear where function calls wouldn't otherwise be appropriate. Technically speaking, macro calls SHOULD parse as function calls.

  Rationale: macros should not allow for hidden syntactic “effects”.

• The code inside a macro definition MUST follow the specifications of these guidelines as a whole.
• The code inside a macro definition MUST NOT contain unbalanced parentheses or unbalanced braces.
• The code inside a macro definition MUST NOT break the control flow using break, continue, return or throw.