Dates in C api

-----Original Message-----
From: Jeff Ryan [mailto:jeff.a.ryan at gmail.com] 
Sent: Wednesday, September 17, 2008 4:19 PM
To: Lee, Philip (IT)
Cc: r-devel at r-project.org
Subject: Re: [Rd] Dates in C api

If you are looking for examples of handling dates/times (specifically
POSIXct) within C code, the dev branch of xts has quite a bit 
of code now.

http://r-forge.r-project.org/plugins/scmsvn/viewcvs.php/dev/pk

Assigning the class (or any attribute) within the C code will 
be much faster than doing it outside of C, at least in my 
experience with larger data.

setAttrib(ans, R_ClassSymbol, mkString("Date"))

HTH
Jeff

On Wed, Sep 17, 2008 at 12:24 PM, Lee, Philip (IT) 
<Phil.Lee at morganstanley.com> wrote:

r-devel,

I've been trying to write a C plugin for R, and I'm struggling to 
understand how dates are represented.

I can create a date in R:

mydate<-as.Date(1, origin="1900-01-01") mydate

[1] "1900-01-02"

When I pass my date to a plugin, though, it's type is that 

of a real.

There doesn't seem to be a date type in Rinternals.h, is 

there a way 

to recognize that a value is a date rather than a real?

Equally, does anyone know if it's possible to create date values in 
the C api?

Thanks,
Phil Lee

Philip Lee
Morgan Stanley | Technology
750 Seventh Avenue, 12th Floor | New York, NY  10019 
Phil.Lee at morganstanley.com
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