On 17/03/2014 11:39, Dirk Eddelbuettel wrote:
Bill, On 17 March 2014 at 12:54, Bill Wang wrote: | Thanks for your reply, I neede convert time_t to R type in C code, can not use | Rcpp. Maybe Rcpp source code could help me. Start by reading 'Writing R Extensions' and figure out how to send an int back and forth. Then cast between int and time_t. Then set the class of the int variable to Date type.
But note that time_t is not 'int' on many modern systems: almost all 64-bit ones and on some 32-bit ones.
I guess this is actually meant to be a date-time object, hence class POSIXct. Class POSIXct is based on doubles, so return a double and add the classes in the R wrapper. If you want class Date, divide by 86400 and return an integer.
That does assume that the system is POSIX-compliant and so ignores leap seconds. I have not encountered one that is not for many years, but allegedly there are locales which do count leap seconds on some Unix-alikes. C code to adjust that is in src/main/datetime.c in the R sources.
-- Brian D. Ripley, rip...@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
