D array to void* and back

[Ali Çehreli via Digitalmars-d-learn]

On 08/03/2015 02:23 PM, ref2401 wrote:

 > void funcLibC_Array(void* data) {
 >      int[] arr = *cast(int[]*)data;

You are still in D, so int[] has a different meaning from a C array. 
(D's arrays are array-like. ;) )

Since arr.ptr is the pointer to the first element, and since that is 
exactly how C functions access array elements, do this:

import std.stdio;

void funcLibC_Array(void* data) {
     int* arr = cast(int*)data;
     writeln("funcLibC_Array: ", arr);

     foreach (i; 0 .. 3) {
         writeln(arr[i]);
     }
}

void main(string[] args) {
     int[] arr = [1, 2, 3];

     funcLibC_Array(arr.ptr); // 'Access Violation error' is thrown here.
}

But you still need to communicate how many elements there are in the 
array. (I used literal 3).

Ali