struct initialisation syntax

Question

I stumbled over a piece of syntax that I have not seen yet and didn't find online, and I wonder what this is:

constexpr struct X{ /* define X members and methods */ } Y{};

What i don't understand is the Y{}.

which part you dont understand? One could write a full article about that single line covering c-heritage up to latest c++ features. — 463035818_is_not_an_ai
– 463035818_is_not_an_ai, Commented Jun 8, 2018 at 9:40
struct X{ /* something here */} defines a struct constexpr Y creates that struct that's a compile time constant called Y {}; initialises the values in the struct — UKMonkey
– UKMonkey, Commented Jun 8, 2018 at 9:44
@UKMonkey I'd make your comment an answer and link to another question that asks about list initialization. Maybe these questions help: stackoverflow.com/questions/41212130/… stackoverflow.com/questions/18222926/…. — miravalls
– miravalls, Commented Jun 8, 2018 at 9:47

Ivaylo Valchev · Accepted Answer · 2018-06-08 09:52:37Z

2

constexpr struct X{ /* something here */} Y{};

is equal to

struct X{ /* something here */};

constexpr X Y{};

For constexpr, check this documentation.

answered Jun 8, 2018 at 9:52

Ivaylo Valchev

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1 Comment

thank you! I missed the fact that you can initialize directly with {}.