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If the objects referenced by arguments to functions overlap (meaning the objects share some common memory addresses), the behavior is undefined. (See also undefined behavior 6865.) The result of the functions is unknown, and data may be corrupted. As a result, these functions must never be passed pointers to overlapping objects. If data must be copied between objects that share common memory addresses, a copy function guaranteed to work on overlapping memory, such as memmove(), should be used.
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