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Noncompliant Code Example (Header Guard)
A common, but noncompliant, practice is to choose a reserved name for a macro used in a preprocessor conditional guarding against multiple inclusions of a header file (see also PRE06-C. Enclose header files in an inclusion guard). The name may clash with reserved names defined by the implementation of the C standard library in its headers or with reserved names implicitly predefined by the compiler even when no C standard library header is included.
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