Function cpp_decoder_from_many 

pub fn cpp_decoder_from_many(
    ast: &Ast,
    roots: &[Id<TypeNode>],
    key: LayoutKey,
    options: CppCodecOptions,
) -> Result<Vec<Decl>, EncodeError>

The C++ decoder for the types several roots reach, each function once.

Errors

As cpp_decoder.