What is the OpenCL analogue for CUDA's __syncthreads() and blockIdx.x?

Question

I am trying to translate CUDA code into OpenCL and right now I am stuck with these functions/variables:

• __syncthreads()
• blockIdx.x

Answer 1

Actually I found it by my own! Here is a useful article: http://www.netlib.org/utk/people/JackDongarra/PAPERS/parcocudaopencl.pdf

The answer is: for the __syncthreads() use barrier(CLK_LOCAL_MEM_FENCE); for blockIdx.x use get_group_id(0)!