multiple-inclusions

Repeated Multiple Definition Errors from including same header in multiple cpps

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Since you’re declaring those variables in the header file, and including the header file in each C++ file, each C++ file has its own copy of them. The usual way around this is to not declare any variables within header files. Instead, declare them in a single C++ file, and declare them as extern in … Read more

Why aren’t my compile guards preventing multiple definition inclusions?

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If the linker is complaining, it means you have definitions rather than just declarations in your header. Here’s an example of things that would be wrong. #ifndef X_H #define X_H int myFunc() { return 42; // Wrong! definition in header. } int myVar; // Wrong! definition in header. #endif You should split this into source … Read more