Are C++ aggregate initializers effective at run time or compile time?

Question

TL;DR : I need global objects to be initialized at compile time, and I cannot use constexpr constructors. Can I use aggregate initializers for this task?

---

I know that C/C++ aggregate initializers can be used to initialize an object's public members like this :

MyObj obj = { "object1", 3, 7.2F };

I discovered their existence not long ago, and I thought about a previous issue I had.

I have a global object with a class type which I'm currently initializing using a constructor :

MyObj obj = MyObj("object1", 3, 7.2F);

This constructor only sets a few members with the given arguments. The problem is that I'd like the object's members to already be initialized inside the application's executable (like a compile-time constructor), which is not the case. Yes, I have inspected the resulting binary file, and the object's space is zeroed.

I cannot use constexpr on the constructor, because I'm working without modern C++ and have no way to upgrade.

This is why I'd like to know if I can use aggregate initializers to solve my issue.

---

EDIT 1 : I forgot to mention that I am developing for Windows, and that the objects I want to initialize have the __declspec(dllexport) and extern "C" specifiers.

Answer 1

As n. 1.8e9-where's-my-share m. said, the terms "compile-time" and "run-time" are meaningless as far as the language is concerned. They are more likely to concern the toolset you're working with.

Best answer I can give here is "uncertain". The behavior of aggregate initializers is not part of the C++ standard, which means it is implementation-defined.

To answer my problem, the best bets I have are either switching to modern C++ and use constexpr constructors, or writing my data in ASM files.