how announce structure header used churned files c?

if i have source.c record struct:

struct { 
    int i;
    struct b {
        int j;
    }
};

how struct used another record (i.e. func.c)?

should i emanate new header file, announce struct there consolidate header func.c?

or should i interpretation whole struct header record consolidate both source.c func.c? struct announced extern both files?

should i typedef it? so, how?

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