C++20 std::format fails

Newbie
,
1

I’m using ROOT with C++20 in Jupyter Notebooks.
I tested some C++20 features. std::span works.
But std::format fails. I ran a notebook with the single line

std::format("Hello World!")

This failed with the error message

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xb8 in position 60000: invalid start byte

I can add that

std::string("Hello World!")

works with output

(std::string) "Hello World!"

Environment:

  • Windows 11
  • ROOT 6.40.02
  • CMake 4.4.0, configured with -DCMAKE_CXX_STANDARD=20.
  • Visual Studio 2022