C considered dangerous

Just be careful if someone might move that into a separate function like "void do_copy(char buf[BUFLEN], ...) { memcpy_s(buf, sizeof(buf), ...); }", and either ignores compiler warnings or is using an older compiler, since sizeof(buf) is now 8 regardless of BUFLEN. C is fun. Better to use a decent ARRAY_SIZE macro (like the one in the Linux kernel) that fails to compile if the argument is not an array.