std::optional

a_unique_name 286 Reputation points
2023-01-12T01:43:04.7166667+00:00

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:

language_property

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

C++
C++
A high-level, general-purpose programming language, created as an extension of the C programming language, that has object-oriented, generic, and functional features in addition to facilities for low-level memory manipulation.
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Accepted answer
  1. YujianYao-MSFT 3,521 Reputation points Microsoft Employee
    2023-01-12T02:10:50.1133333+00:00

    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.

    enter image description here enter image description here

    Best regards,

    Elya


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1 additional answer

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  1. a_unique_name 286 Reputation points
    2023-01-12T01:50:32.1366667+00:00

    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?

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