[R] help in R calling C function

[Lei Liu]

Hi there,

I want to call a C function in R. I have some experience on it, but this 
time I need to call another C function in the "main" C function. As a 
simple example, I use the following C code:

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>


void main(double *alpha)
{
	double test();
	double beta;
	beta= *alpha *2 + test(*alpha);
}

double test(double *alpha)
{
	double value;
	value = *alpha *3;
	return(value);
}

I used "gcc -c main.c" and "Rcmd SHLIB main.o" and I got the main.dll file. 
In R I use the following code to call the C function "main":

dyn.load("c:/Program Files/R/rw1060/bin/main.dll")
a=4.2
b=.C('main', as.double(a))

But the R system crashed. I know I can only define the function type in C 
as "void" to be called by R. But what if I want to call another C function 
in the "main" C function? Thank you for your help!

Sincerely,

Lei Liu