That's not the problem. If time_t was a struct with a single int32_t, you'd be in the same situation when you changed it to int64_t (ABI incompatibility: you ne

That's not the problem. If time_t was a struct with a single int32_t, you'd be in the same situation when you changed it to int64_t (ABI incompatibility: you need more space to store the value now). In order not to have this problem you'd need the API to use opaque struts, for which only pointers would be exchanged.