[R] R-1.4.0: how to use getSymbolInfo()?

[Setzer.Woodrow@epamail.epa.gov]

Thanks, Duncan.  That is exactly what I was looking for!  and yes, it is
getNativeSymbolInfo(); sorry for the confusion.

R. Woodrow Setzer, Jr.                                            Phone:
(919) 541-0128
Experimental Toxicology Division                       Fax:  (919)
541-5394
Pharmacokinetics Branch
NHEERL MD-74; US EPA; RTP, NC 27711


                                                                                                                              
                    Duncan Temple Lang                                                                                        
                    <duncan at research.bell        To:     Woodrow Setzer/RTP/USEPA/US at EPA                                      
                    -labs.com>                   cc:     r-help at stat.math.ethz.ch                                             
                                                 Subject:     Re: [R] R-1.4.0: how to use getSymbolInfo()?                    
                    12/15/01 11:10 AM                                                                                         
                                                                                                                              
                                                                                                                              




Setzer.Woodrow at epamail.epa.gov wrote:
>
> Welll, getSymbolInfo() returns a list that includes an external
pointer
> object.  I guess my question is, how to unwrap it in the c code so
that
> I can use it as (*f)()?

Hi Woodrow,

  I have been away from the office for the past few days, so didn't
get your mail until now. Just in case you haven't got an answer, here
is one.

  As you correctly point out, what you need is a way to unwrap the
external pointer. The C routine R_ExternalPtrAddr() will do this
for you.

  Your situation is one of the contexts that motivated adding the
reflectance information about native symbols. We can pass R functions
or "NativeSymbol" objects and have C code handle them appropriately.
I put together two examples of the mechanism and they are available
at
  http://cm.bell-labs.com/stat/duncan/RSymbolInfo.tar.gz

The file basic.c shows what you need to do.  chandler.c shows how to
handle either an R function or a NativeSymbol object.

BTW, it is getNativeSymbolInfo() rather than getSymbolInfo(), isn't it?

 Duncan.

>
> R. Woodrow Setzer, Jr.
Phone:
> (919) 541-0128
> Experimental Toxicology Division                       Fax:  (919)
> 541-5394
> Pharmacokinetics Branch
> NHEERL MD-74; US EPA; RTP, NC 27711
>
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--
_______________________________________________________________

Duncan Temple Lang                duncan at research.bell-labs.com
Bell Labs, Lucent Technologies    office: (908)582-3217
700 Mountain Avenue, Room 2C-259  fax:    (908)582-3340
Murray Hill, NJ  07974-2070
         http://cm.bell-labs.com/stat/duncan




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