How do you read arguments passed to a native kernel? - opencl

Question

I have a native kernel setup but I don't know how to convert its void* argument into anything useful. In the native kernel of this snippet, how would I get the int (7) or the int[] (16 ints set to 0)?
void __stdcall nativeKernel(void * args)
{
int a1 = (*(int*)args);
cout << "a1-->: "<< a1 << endl; // gibberish
}
void kernelCaller()
{
const int dim1Size = 16;
int dim1[dim1Size] = {};
cl_int status = 0;
cl_mem mem_d1 = clCreateBuffer(*context, 0, sizeof(int)*dim1Size, NULL, &status);
clEnqueueWriteBuffer(*queue, mem_d1, CL_TRUE, 0, sizeof(int)*dim1Size, dim1, 0, NULL, NULL);
const void* args[2] = {(void*)7, NULL};
cl_mem mem_list[1] = {mem_d1};
const void* args_mem_loc[1] = {&args[1]};
cl_event run;
status = clEnqueueNativeKernel(*queue, nativeKernel, args, 2, 1, mem_list, args_mem_loc, 0, NULL, &run);
status = clEnqueueReadBuffer(*queue, mem_d1, CL_TRUE, 0, sizeof(int)*dim1Size, dim1, 1, &run, NULL);
for(auto i = 0; i != dim1Size; i++)
cout << dim1[i] << " ";
}

Answer 1

instead of playing hard with void* i would like to suggest to use struct
create your parameter structure like:
struct myparams{
int a
int a[3];
};
and then create and fill one struct myparams in your program and pass its address to the kernelcaller
struct myparams params;
params.a=3;
status = clEnqueueNativeKernel(*queue, nativeKernel, (void*)&params, 2, 1, mem_list, args_mem_loc, 0, NULL, &run);
and in the nativeKernel just unbox the void* into your parameter struct:
struct myparams *params=(myparams*)args;
beware: in the example above i passed a pointer of the stack...you might not want that ;)