It is true that there is C code that is conforming C++ code. However I would say if you’re using a C compiler with with “extern C” in the headers for C++ linker compatibility (as this library does) then saying C++ is about as misleading as saying a Rust library is C++ as you can link to that too.

As far as compatibility and “history” the languages are different enough now. There are both: features in C that do not exist in C++, and code that is conforming C that would be UB in C++. Saying C/C++ (for real) is usually a dumb target when it’s better to pick one and settle with that.

If it’s C, just say so. Everyone knows what extern C is, you don’t need to confuse.

Something very close, but that's not what you would expect for something that markets itself as a C++ library IMHO. Especially in 2024, most people would hope (or assume) that "C++" means "C++ 11" at least.

Definitely doesn't count as _lying_, but still underwhelming.

Yes. And C can also be used with Python and Rust. That does not make this a Rust library.

  #ifdef _cplusplus
      #include <iostream>
      #define print() int main(){cout << "Hello world! -- from C++" << endl;}
  #elif (defined __STDC__) || (defined __STDC_VERSION__)
      #include <stdio.h>
      #define print() int main(){printf("Hello world! -- from C\n");}
  #else
  import builtins
  print = lambda : builtins.print("Hello world! -- from Python")
  #endif
  
  print()

Some python code works in C and C++ as well but people don't group them together and call Python/C/C++

Depends, not all C is C++, eg, there is no (yet) `restrict` keyword in C++ (even if lots of C++ compilers support __restrict__, it's not in the spec)