libpqxx库中没有pqxx :: tuple？

Question

I ve got the newest ubuntu and I ve done:

sudo apt-get install postgresql postgresql-contrib
sudo apt-get install libpqxx-4.0v5
sudo apt-get install libpqxx-dev

I can`t compile program which uses pqxx::tuple.

Compilation:

g++ test.cpp -I/usr/local/include/ -lpqxx -lpq
or
g++ test.cpp -lpqxx -lpq -o test

Console output:

test.cpp: In function ‘int main()’:
test.cpp:15:21: error: ‘tuple’ in namespace ‘pqxx’ does not name a type
const pqxx::tuple row = r[rownum];

This is the problematic line:

const pqxx::tuple row = r[rownum];

When I remove this line, program works correctly.

#include <iostream>
#include <pqxx/pqxx>
int main()
{
  try {
    pqxx::connection c("dbname=mydb user=postgres port=5432 password=*** hostaddr=127.0.0.1");
    pqxx::work w(c);
    pqxx::result r = w.exec("SELECT * FROM get_player_data_function()");
    w.commit();
    const int num_rows = r.size();
    for (int rownum=0; rownum < num_rows; ++rownum) {
        const pqxx::tuple row = r[rownum];
    }
  }
  catch (const std::exception &e) {
    std::cerr << e.what() << std::endl;
  }
}

Answer 1

Not sure... but if I understand correctly this page , you have to substitute pqxx::tuple with pqxx::row .

So, I suppose

const pqxx::row row = r[rownum];