# Extra Clang Tools 22.1.2 documentation

## clang-tidy - misc-anonymous-namespace-in-header

# misc-anonymous-namespace-in-header

Finds anonymous namespaces in headers.

Anonymous namespaces in headers can lead to One Definition Rule (ODR) violations because each translation unit including the header will get its own unique version of the symbols. This increases binary size and can cause confusing link-time errors.

## References

This check corresponds to the CERT C++ Coding Standard rule DCL59-CPP. Do not define an unnamed namespace in a header file.

Corresponding cpplint.py check name: build/namespaces.