constant
<utility>
std::piecewise_construct
constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
Piecewise construct constant
This constant value is passed as the first argument to construct a pair object to select the constructor form that constructs its members in place by forwarding the elements of two tuple objects to their respective constructor.
Example
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| // piecewise_construct example #include <utility> // std::pair, std::piecewise_construct #include <iostream> // std::cout #include <tuple> // std::forward_as_tuple #include <vector> // std::vector #include <string> // std::string int main () { std::pair < std::string, std::vector<int> > foo ( std::piecewise_construct, std::forward_as_tuple("test"), std::forward_as_tuple(3,10) ); std::cout << "foo.first: " << foo.first << '\n'; std::cout << "foo.second:"; for (int& x: foo.second) std::cout << ' ' << x; std::cout << '\n'; return 0; }
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Output:
foo.first: test foo.second: 10 10 10 |
See also
- pair::pair
- Construct pair (public member function)