Passing a global parameter from kernel into a function

I’m just playing around with OpenCL and trying to get some simple c++ routines adapted for opencl.

Basically - i’m trying to do something of the kind:

// function prototype
int CL_TestFunction(float2 *pts)

// opencl kernel
kernel void CL_TestKernel(global float2 *pts)
  // so let's do some stuff 
  int id = get_global_id(0);
  // blah
  float x = pts[id].x;
  float y = pts[id].y;
  // and then let's use a c style function, which passes in the array of float2 
  int num = CL_TestFunction(pts);  

int CL_TestFunction(float2 *pts)
  // do some things in here:
  return 0;

Now - the problem i’m getting is when i try passing in the pts array into the CL_TestFunction. I get a build error.
When i’ve used other functions, which don’t use the global parameters, it’s absolutely fine (to my knowledge anyway).

So - i’m guessing that i’m unable to do this. So - is there a way around this? I imagine i’m missing the point somewhat in regards global variables etc, so any help would be really appreciated.
The code i’m working on is a lot more complicated than what i’ve displayed above, so there are good reasons (to me) for trying to pass the pts array.

Hope that makes some sort of sense.

Ran into the same problem without any solution. I think it is because this funktion will loose the qualifier global. But I’m not really shure. I think i found someting in the spec, regarding that topic

Your function should be declared as “CL_TestFunction(global float2 *pts)”

Without an explicit address space qualifier, a pointer is considered as private, so “CL_TestFunction(float2 *pts)” really means “CL_TestFunction(private float2 *pts)”.

Thanks, i got that to build!

Now to sort the rest of it out :slight_smile: