# Extra Clang Tools 21.1.6 documentation

## clang-tidy - readability-duplicate-include

# readability-duplicate-include

Looks for duplicate includes and removes them. The check maintains a list of included files and looks for duplicates. If a macro is defined or undefined then the list of included files is cleared.

Examples:

    #include <memory>
    #include <vector>
    #include <memory>

becomes

    #include <memory>
    #include <vector>

Because of the intervening macro definitions, this code remains unchanged:

    #undef NDEBUG
    #include "assertion.h"
    // ...code with assertions enabled

    #define NDEBUG
    #include "assertion.h"
    // ...code with assertions disabled