KISS MY ASCII GOOD PI!

[Kernelpanic]

Why not just "printf" instead of "__mingw_printf"? Because you're including "stdio.h" then "printf()" should be available. I tried to compile your program as it was, "gcc" asked me if I meant "builtin_printf()" or alike. After I forgot what option for linker so it links to math library...

"__mingw-printf" is for representing large numbers like long double.

So, "__mingw_printf("%.12Lf"...) is for displayin great numbers.