32     std::ifstream fs;  in main()  local
33     assert(!fs.is_open());  in main()
35     fs >> c;  in main()
36     assert(fs.fail());  in main()
38     fs.open(std::filesystem::path("test.dat"));  in main()
39     assert(fs.is_open());  in main()
40     fs >> c;  in main()
45     std::wifstream fs;  in main()  local
46     assert(!fs.is_open());  in main()
48     fs >> c;  in main()
49     assert(fs.fail());  in main()
51     fs.open(std::filesystem::path("test.dat"));  in main()
52     assert(fs.is_open());  in main()
53     fs >> c;  in main()