Consteval error on C++20

[TheCompez]

Hi,
As you know we can't use constexpr variables in function parameter.
But I need use function parameters from other json files.

Example :

std::string functionTest(std::string_view content, const std::string& value) {
  return fmt::format(content, value);//Error on compile time :)
}
std::cout << functionTest("The answer is {number}",  10);

How can I solve this problem?

Error:

error: call to consteval function 'fmt::basic_format_string<char, std::string>::basic_format_string<std::string, 0>' is not a constant expression
error: call to consteval function 'fmt::basic_format_string<char, std::string>::basic_format_string<std::string, 0>' is not a constant expression
  return fmt::format(text, val);
                     ^
note: non-literal type 'std::string' (aka 'basic_string<char>') cannot be used in a constant expression

[vitaut]

You can wrap the format string in fmt::runtime to disable compile-time checks:

std::string functionTest(std::string_view content, const std::string& value) {
  return fmt::format(fmt::runtime(content), value);
}

or pass it as format_string as {fmt} does.

[TheCompez]

You can wrap the format string in fmt::runtime to disable compile-time checks:

std::string functionTest(std::string_view content, const std::string& value) {
  return fmt::format(fmt::runtime(content), value);
}

or pass it as format_string as {fmt} does.

Thanks for your attention! @vitaut :)