CODEWITHSUNDEEP
c++constructorc++17
QuaternionsRock
QuaternionsRock

Reputation: 922

Is it possible to use structured binding in the member initializer list of a constructor?

I would like to create a class with several const member variables. Unfortunately, the function I need to initialize those variables is from a very C-style external library. As a result, I have been employing the following "middle-man" of sorts:

struct Struct {
    int foo, bar;
    Struct(int baz, int qux) {
        initializerFunction(&foo, baz, &bar, qux);
    }
}
class Class {
    const int foo, bar;
    Class(Struct s) : anArray(s.foo), anotherArray(s.bar) {}
public:
    Class(int baz, int quz) : Class(Struct(baz, qux)) {}
}

However, I somewhat dislike this construction. I was hoping to be able to do something like this instead:

class Class {
    const int foo, bar;
public:
    Class(int baz, int qux) : [foo, bar](Struct(baz, qux)) {}
}

Is it possible that I am just using incorrect syntax, or is structured binding truly not allowed in the member initializer list of a constructor?

Upvotes: 4

Views: 684

Answers (1)

Nicol Bolas
Nicol Bolas

Reputation: 473577

Structured bindings declare variables (well, they're not "variables" per-se, but nevermind). You cannot use structured bindings to manipulate existing objects. This includes member objects.

Upvotes: 6

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