> This means that time_t had to be tracked down on varying architectures > to find the size and there was an assumption made that time_t is 32 bits > - which isn't true for all targets. The next problem is that if the > target is 32 bits but the host is 64 bits then there's a sign extension > problem because (time_t)-1 is used for an error condition. If you don't > correctly assign assign the 32-bit -1 to a 64-bit type then, rather than > -1, you get 4294967295.
Is there any guarantee that time_t is a signed type? The fact that you said (time_t)-1 suggests it could be an unsigned type. If time_t is an unsigned type, then casting to a wider value is still wrong. You have to special-case the error condition. In the case of time_t this only becomes relevant after 32-bit time_t wrap in approx. 99 years time, but I'd expect there are cases where it matters. Paul
