On Thu, 28 Mar 2013, Brandon Allbery wrote:

If CTime is only for interfacing with C, then there should not be any arithmetic or bit manipulation
class instances of it, only some conversion functions between CTime and Haskell time representations.

...and implementing those should be as painful as possible?

Implementing these conversion functions means unpacking data from the CTime constructor and convert it to Haskell time representations or vice versa. I don't think it is possible to write conversion functions using Num and Bits that work on all architectures. If there is functionality that can be used on multiple architectures this should be provided as helper functions.