Windows CE does not support the full set of time_t functions in time.h from the C Standard Library, so porting code that uses functions such as mktime, difftime, strftime and the like can be a bit tedious.

OpenNETCF offers the completely free and open-source OpenTimeCE library as an aid to get you working on your actual application instead of the grunt-work of porting.

UPDATED July 5, 2007: Bug fixes for timezone UTC offset (see source for more info)

Download the OpenTimeCE source here