What is the reason for requiring the same tags in structure type declarations of different translation units for compatibility?

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The reason for requiring the same tags in structure type declarations of different translation units for compatibility is to ensure that the same structure is being used throughout the program. If different translation units declare the same structure with different tags, it could lead to confusion and errors when the data is passed between different parts of the program. By requiring the same tags in all declarations of the same structure, the compiler can ensure that the structure is consistent and that data can be passed between different parts of the program without issue.