[ecesena]

It's C :) edit: It's Linux kernel :)

    /* current power of three, init to 3^0 */

[spiralpolitik]

// became valid C in C99. 15 years ago.

[ecesena]

Sorry, I should have said it's Linux kernel [1].

    Linux style for comments is the C89 "/* ... */" style.
    Don't use C99-style "// ..." comments.

[1] https://www.kernel.org/doc/Documentation/CodingStyle