CODEWITHSUNDEEP
c++c++17structured-bindings
Klaus
Klaus

Reputation: 25593

structured binding with existing vars not possible?

Is it possible to use already existing vars as target for return values in connection with structured bindings?

auto f()
{
    return std::make_tuple(1,2.2);
}

int main()
{
    int x;
    double z;

    [ x, z ] = f();  // Did not work in gcc 7.1

    // structured bindings only work with "new" vars?
    auto [a, b] = f();  // works fine
}

Upvotes: 11

Views: 2552

Answers (1)

StoryTeller - Unslander Monica
StoryTeller - Unslander Monica

Reputation: 170044

If you want to use existing variables, you have std::tie for that purpose.

std::tie(x, z) = f(); // only works with tuples however

Structured bindings introduce new identifiers. Unfortunately there is nothing equivalent to std::tie for general aggregates.

Upvotes: 15

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