[R] Trouble passing arrays to C code

[Wee-Jin Goh]

Hello,

I'm having more trouble with interfacing with C code. I have a  
function in C that will return the result of its computation as 3  
arrays. The signature of the function is as follows:

void lorenz_run(double x0, double y0, double z0, double h, int steps,
					double *res_x, double *res_y, double *res_z)

The function works, as I've tested it from within C itself and the  
results it gives are accurate. In order to integrate it with R, I've  
written the following C wrapper function:

void lorenz_run_R_wrapper(double *x0, double *y0, double *z0, double  
*h, double *steps,
			double *res_x, double *res_y, double *res_z) {
	lorenz_run(*x0, *y0, *z0, *h, *steps, res_x, res_y, res_z);	
}

The corresponding R wrapper function is:

lorenz_run <- function(x0,y0,z0,h,steps) {
	returned_data = .C("lorenz_run_R_wrapper",
                        x0=as.double(x0),
                        y0=as.double(y0),
                        z0=as.double(z0),
                        h=as.double(h),
                        steps=as.integer(steps),
                        res_x=double(steps),
                        res_y=double(steps),
                        res_z=double(steps))
      # Return the value of the result parameter
      return( rbind(returned_data$res_x, returned_data$res_y,  
returned_data$res_z))

}

My problem is, that the first elements of res_x, res_y, and res_z are  
correctly set. But the rest of the cells in those 3 arrays remain 0.  
This leads me to think that I am passing these arrays to the C code  
wrongly. Can anyone help me out?

Thanks in advance,
Wee-Jin