int i = 0;
  
kernel void extExec(__global int* res) {

  queue_t q1 = get_default_queue();
  size_t global_size = get_global_size(0);
  ndrange_t ndrange = ndrange_1D(global_size);

  void (^kernelBlock)(void) = ^{ i = 1; };
  if(res) {
    kernelBlock = ^{ i = 2; };
  }
  int enq_res = enqueue_kernel(q1, CLK_ENQUEUE_FLAGS_WAIT_KERNEL, ndrange, kernelBlock);
}