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How to include library feature macros like __cpp_lib_* if importing std only?

JUANDENT (411)
the library feature macros __cpp_lib_* are defined in header yvals_core.h (for visual C++) which is an implementation header and thus not meant to be included in cross platform libraries... So how can we obtain these macros in 3rd party library code that uses the standard library via 

 
 
import std;


?



Last edited on
deleted account xyzzy (5768)
You do realize C++ code can still #include headers even with imports?
Peter87 (11234)
And you only need to include one header.

#include <version>

https://en.cppreference.com/w/cpp/header/version
Including <version> also defines all library feature-test macros.
Last edited on
JUANDENT (411)
Yes I know I can #include
Thanks!
deleted account xyzzy (5768)
Even though <version> was added to C++20 it isn't automatically added when using C++23's import std; or import std.compat; It has to be manually imported/#included to get access to the macros.

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import std;
import <version>;

int main( )
{
   std::cout << __cpp_lib_any << '\n';
}


Compiles with nary a problem with VS 2022 as long as the C++ language standard is set to latest.
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