Why max_align_t not defined in stddef.h in Windows SDK 10.0.20348.0 C17 (/std:c17)

zhimin yuan 0 Reputation points
2024-06-24T13:33:18.9533333+00:00

#include <stdio.h>

#include <stddef.h>

int main(void)

{

printf("%d\n", _Alignof(max_align_t));
```}

This C code, Error: E0020, C2061, in Visual Studio Community 2019 16.11.17, Windows SDK 10.0.20348.0, C17 or C11  

The same error appears in Visual Studio Community 2022, Windows SDK 10.0.22000.0, C17 or C11

 maybe a bug: "max_align_t not defined in stddef.h in Windows SDK"

Welcome to try, Thanks!
Windows API - Win32
Windows API - Win32
A core set of Windows application programming interfaces (APIs) for desktop and server applications. Previously known as Win32 API.
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  1. Jeanine Zhang-MSFT 9,431 Reputation points Microsoft Vendor
    2024-06-25T01:50:14.59+00:00

    Hello,

    Welcome to Microsoft Q&A!

    I suggest you could try to use #include <cstddef> instead of #include <stddef.h>.

    It seems that it's only supported in C++ right now. There is no definition of max_align_t in stddef.h.

    And someone has raised a similar issue but it was closed because it was lower priority, and if your issue is tricky, I suggest you could post another issue.

    You could also refer to the thread: https://github.com/emscripten-core/emscripten/pull/8908

    Thank you.

    Jeanine

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