alt Hacker NewsODR violations are very easy to trigger unless you build the whole thing from source, and are ill-formed, no diagnostic required (worse than UB).
ODR violations are very easy to trigger unless you build the whole thing from source, and are ill-formed, no diagnostic required (worse than UB).
Neither "ODR violations" nor IFNDR exist in C. Incompatibility across translation units can cause undefined behavior in C, but this can easily be avoided.