The road to Zettalinux

Well, does "Unix" say anything about the size of time_t? No, it's the implementation specific ABI which is largely defined by the hardware architecture. Of course C, the library, and time_t all originated from Unix.

My point was that the C standard library time functions are used outside of Unix: in a shipload of Windows software, and a megaton of embedded software that has traditionally been implemented i C and typically uses the C standard library that comes with the compiler.

OK, Unix defines time zero, but how many non-Unix systems using the libc API have defined it differently?