This package offers C-level datetime code from R for C-level use by other packages.
If you are writing C (or C++) code in an R package which needs to parse, format or transform date(time) objects, and want to do this at the compiled level, i.e. faster than calling back to the corresponding R level function could do it.
Dirk Eddelbuettel put the package together, but the underlying code is by the R Core team (and in parts the C library authors).
GPL (>= 2) just like R itself
The package, while young, can be considered stable as the actual code is fairly mature and stable.
Dirk Eddelbuettel for this package; and R Core for the parts taken from R.