out of the blue, this routine causes some pain in the ***

Care to clarify what you mean?

In the last sentence under remarks, the article says:

"..; for x64 compilers it is 4K and 8K respectively."

Respecively to what? 4k is 4096 - so why the difference?

Does the remark mean that fo X86 compilers, the routine is called when local variables exceed 4k (4096 bytes) while for X64 compilers when they exceed 8k (8192 bytes)? Or something else?

What I can't understand is why I can't create a variable on the stack with more than 4KB bytes. Besides, if that's the case, why doesn't the compiler warns me before hand that the code will fail?