How to declare a function that accept pointer to any type

Hello,

I am working on OpenCL 2.0 implementation.
In OpenCL 2.0, there are functions like:
__local T * to_local(T *p)
__global T *to_global(T *p)

Here T can be any builtin type or user defined type.
How to make declaration of such kind of function in a header file?

Thanks!
Ruiling