Question

Here’s the code that I have a problem with:

class Foo {
public:
    Foo() :
        memberArray{Bar(1), Bar(3), Bar(2)}
    {}
    struct Bar {
        Bar(int param1) {  }
    };
private:
    std::array<Bar,3> memberArray;
//  Bar memberArray[3];    // Using a raw array like this instead compiles fine..
};

I’m using GCC 4.6.1, and compiling for c++11. How should I initialise my std::array?

Answer 1

Since array<T, N> is actually a struct, the fully braced version needs {{ .. }} (the inner ones are for the array member of the array<T, N> object). The spec does not allow brace elision here. It only allows it in a declaration of the form

Type var = { ... };

So you have to use fully braced syntax

Foo() :
    memberArray{{Bar(1), Bar(3), Bar(2)}}
{}

This is not a GCC bug, but required by the spec.