[R] Using C code in R

[Steve Lianoglou]

Trying to send to the list, take 3 (for some reason my mails get
bounced when I send to r-help at r-project.org, and not when I send to
r-help at stat.math.ethz.ch)

On Thu, Mar 24, 2011 at 8:34 PM, Steve Lianoglou
<mailinglist.honeypot at gmail.com> wrote:
> Hi Jaimin,
>
> Please include r-help in your reply -- it's not included by default,
> so you'll have to use your email client's "reply all" functionality
> when responding to posts coming from the mailing list.
>
> This way (i) more people will be able to help you than just me; and
> (ii) if someone runs into the same/similar problem you are having down
> the road, a web search might land them on this thread -- anyway:
>
> On Thu, Mar 24, 2011 at 5:55 PM, Jaimin Dave <davejaiminm at gmail.com> wrote:
>> Thanks for help...
>> I  am sorry i just forgot to declare global variable in previous function
>> .But after I declare and compile it is showing following error:
>> HelloWorld.c: In function 'sayhello':
>> HelloWorld.c:9:2: warning: implicit declaration of function 'Rprintf'
>> x86_64-w64-mingw32-gcc -shared -s -static-libgcc -o HelloWorld.dll tmp.def
>> Hello
>> World.o -LC:/PROGRA~1/R/R-212~1.1/bin/x64 -lR
>> HelloWorld.o:HelloWorld.c:(.text+0x44): undefined reference to `sayHello'
>> collect2: ld returned 1 exit status
>>
>> It is saying that undefined reference to function sayHello
>> Could you help me on this?
>
> Look at your code again. In your initial declaration of 'sayHello',
> you spell it like this:
>
> void sayHello();
>
> Then your implementation of it is:
>
> void sayhello() { ... }
>
> (note the case of the letters)
>
> And inside your `g` function you are calling `sayHello` (which still
> hasn't been defined).
>
> Also, I'm pretty sure you shouldn't be getting this warning:
>
> HelloWorld.c:9:2: warning: implicit declaration of function 'Rprintf'
>
> Is your include statement really preceded by `//`? like:
>
> //#include <R.h>
>
> ?
>
> -steve
>
>
>> On Wed, Mar 23, 2011 at 11:58 PM, Steve Lianoglou
>> <mailinglist.honeypot at gmail.com> wrote:
>>>
>>> Hi,
>>>
>>> On Wed, Mar 23, 2011 at 8:12 PM, Jaimin Dave <davejaiminm at gmail.com>
>>> wrote:
>>> > Hi,
>>> > I am new to R and I want to know how to use C code which contains two
>>> > functions one called inside another.I know that how to use C code in R
>>> > if it
>>> > has only one function but dont know how to do it in above case.
>>>
>>> There's no special case to consider here.
>>>
>>> You would call the "outer" C function from R, and let your C function
>>> call whatever other C functions it wants, ie:
>>>
>>> > use the same in R .My C code is as follows.
>>> >
>>> > //#include <R.h>
>>> >
>>> > void sayHello();
>>> >
>>> > void g();
>>> >
>>> >
>>> >
>>> > void sayhello() {
>>> >
>>> > Rprintf("Hello world %d\n",global);
>>> >
>>> > }
>>> >
>>> > void g()
>>> >
>>> > {
>>> >
>>> > int a=9;
>>> >
>>> > int b=1;
>>> >
>>> > Rprintf("Hello world\n %d",(a+b));
>>> >
>>> > sayHello();
>>> >
>>> > }
>>> >
>>> > Help would be greatly appreciated
>>>
>>> Assuming you set up your R <--> C stuff correctly, you'd just have R
>>> call your `g` function.
>>>
>>> I don't see where you have the `global` variable defined (it's used in
>>> your `sayHello` function) so this will fail for other reasons, but
>>> assuming all of your C stuff is works, then just having R call `g`
>>> correctly will work for you.
>>>
>>> -steve
>>>
>>> --
>>> Steve Lianoglou
>>> Graduate Student: Computational Systems Biology
>>>  | Memorial Sloan-Kettering Cancer Center
>>>  | Weill Medical College of Cornell University
>>> Contact Info: http://cbio.mskcc.org/~lianos/contact
>>
>>
>
>
>
> --
> Steve Lianoglou
> Graduate Student: Computational Systems Biology
>  | Memorial Sloan-Kettering Cancer Center
>  | Weill Medical College of Cornell University
> Contact Info: http://cbio.mskcc.org/~lianos/contact
>



-- 
Steve Lianoglou
Graduate Student: Computational Systems Biology
 | Memorial Sloan-Kettering Cancer Center
 | Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact