Hi Dirk,
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.
Cheers,
Bill
2014-03-16 22:55 GMT+08:00 Dirk Eddelbuettel <e...@debian.org>:
>
> On 16 March 2014 at 18:36, Bill Wang wrote:
> | I am writing a R extensions, and I need pass time_t to R in C, but I
> don't
> | know how to do.
> | Can you give me some help? do not use double directly.
>
> Just treat it as an int:
>
> R> library(Rcpp)
> R> cppFunction("Date time_t2date(time_t what) { return((int) what); }")
> R> time_t2date(0)
> [1] "1970-01-01"
> R> time_t2date( Sys.Date() )
> [1] "2014-03-16"
> R>
>
>
> Here I use Rcpp to define the 'time_t2date' function on the fly.
>
> It takes the time_t and returns a Date type (which here is a C++ Date type
> mapping to the R Date -- you can ignore that, but will have to write the
> legwork yourself if you don't use Rcpp).
>
> As 'time_t' is 'long int' on my system, so I cast it to int. The rest is
> automagic (thanks to RcpP).
>
> Notice that I also get today's date down and up correctly.
>
> See 'Writing R Extensions' for the details at the C level.
>
> See the Rcpp documentation (and, if I may, my book) for details on Rcpp if
> that interests you.
>
> Dirk
>
> --
> Dirk Eddelbuettel | e...@debian.org | http://dirk.eddelbuettel.com
>
--
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