The following code prints out 'wg size 1', instead of 'wg size 3', which is the expected value: #include <unordered_map> #include <initializer_list> int main(void) { const std::pair<const long, wchar_t>             wp0(0, L'i'), wp1(1, L'm'), wp2(2, L'p');         std::initializer_list<std::unordered_map<long, wchar_t>::value_type>             winit { wp0, wp1, wp2 }; std::unordered_map<long, wchar_t> wg(winit);         printf("wg size %zu\n", wg.size()); }