How does this Array Size Template Work?

I came across this snippet

template <typename T, size_t N>  
char (&ArraySizeHelper(T (&array)[N]))[N];  
#define arraysize(array) (sizeof(ArraySizeHelper(array))) 

in this article http://software.intel.com/en-us/articles/pvs-studio-vs-chromium/

I've seen other templates to do the same thing, like this one

Use templates to get an array's size and end address

and I understand those, but I've been having difficulty with this one.

Any help would be appreciated.