foo.cc: In function ‘void compute_row(int, int, std::vector<__int128>&, const std::vector<__int128>&)’:
foo.cc:36:5: error: ‘function’ was not declared in this scope
   36 |     function<void(int, int, int, int)> divide = [&](int l, int r, int optL, int optR) {
      |     ^~~~~~~~
foo.cc:5:1: note: ‘std::function’ is defined in header ‘<functional>’; this is probably fixable by adding ‘#include <functional>’
    4 | #include <cstring>
  +++ |+#include <functional>
    5 | using namespace std;
foo.cc:36:37: error: expression list treated as compound expression in functional cast [-fpermissive]
   36 |     function<void(int, int, int, int)> divide = [&](int l, int r, int optL, int optR) {
      |                                     ^
foo.cc:36:14: error: expected primary-expression before ‘void’
   36 |     function<void(int, int, int, int)> divide = [&](int l, int r, int optL, int optR) {
      |              ^~~~