Date: Sun, 04 Oct 1998 12:03:49 +0100 From: Markus Kuhn <Markus.Kuhn@cl.cam.ac.uk> You certainly do not measure the position of your radio telescope with 3 cm precision (0.1 ns) by performing time request calls to your C API! You would use external picosecond hardware phase comparators clocked by caesium time normals, which send you the data as ASCII floating point numbers for further processing in your Fortran tools It sounds like you're saying that C should not support high-resolution timestamps, and that people who need such things should use Fortran instead. Perhaps I'm paraphrasing you incorrectly; still, I am extremely uncomfortable with the idea that the C standard should impose an upper limit on the quality of the clock. It's reasonable for the C Standard to impose a _lower_ limit on clock quality, just as it imposes a lower limit on the size of `int'. But it's not reasonable for the standard to impose an upper limit, unless there is a compelling justification, which is absent here. The standard places no upper bound on the size of `int', and this is for a good reason: we don't want to forbid higher-quality implementations. I can't offhand recall any place in the existing standard that imposes an upper bound on quality; I don't think <time.h> should either.