Are Elipses in case statements standard C/C++

I was browsing some code in the linux kernel and I came across the statements like `case '0' ... '9':` To try this out I created the test program below. ``` #include <iostream> int main() { const int k = 15; switch (k) { case 0 ... 10: std::cout << "k is less than 10" << std::endl; break; case 11 ... 100: std::cout << "k is between 11 and 100" << std::endl; break; default: std::cout << "k greater than 100" << std::endl; break; } } ``` The program above does compile although I have never come across the elipses in case statement construct before. Is this standard C and C++ or is this a GNU specific extension to the language?