std::optional

Question

Hi Folks:

Developing with Visual Studio, updated today to version 17.4.4.

I'm starting the Vulkan tutorial and I'm stuck at:

https://vulkan-tutorial.com/Drawing_a_triangle/Setup/Physical_devices_and_queue_families

I can't get Code Block to work for me, so here's the code:

struct QueueFamilyIndices {
std::optional<uint32_t> graphicsFamily;

bool isComplete() {  
    return graphicsFamily.has_value();  
}  

};

The errors are on the std::optional statement.
error C2039: 'optional': is not a member of 'std'
error C7568: argument list missing after assumed function template 'optional'

Here's Project Properties -> C++ -> Language:

I've tried different C++ Language Standard, Conformance mode and even C Language Standard, with no effect.

https://en.cppreference.com/w/cpp/utility/optional shows a c++17 compliant compiler should be able to handle std::optional.

What am I doing wrong?

Thanks
Larry

Answer 1

Hi @a_unique_name，

After testing, std::optional can be used in VS.

I suggest you to add <optional> header file and set c++ language standard.

Best regards,

Elya

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Answer 2

The Forum software is sticking part of the code inside a code block, but not all of it.

I already wasted an hour trying to put it inside of a code block, erased everything and recomposed the question, without a code block.

Everything I try to do just makes it more unreadable.

The code is the struct, the error is the std::optional, and the code block is around a function in the struct that doesn't even need to be there, but not work another half an hour trying to fix.

I'm not a fan of the forum software. Looks like something Microsoft would build.

Does anybody else prefer the forum software we had with MSDN?