28 namespace fs = std::filesystem;
31   fs::path p = get_temp_file_name();  in main()
33     std::ofstream fs;  in main()  local
34     assert(!fs.is_open());  in main()
36     fs << c;  in main()
37     assert(fs.fail());  in main()
38     fs.open(p);  in main()
39     assert(fs.is_open());  in main()
40     fs << c;  in main()
43     std::ifstream fs(p.c_str());  in main()  local
45     fs >> c;  in main()
52     std::wofstream fs;  in main()  local
53     assert(!fs.is_open());  in main()
55     fs << c;  in main()
56     assert(fs.fail());  in main()
57     fs.open(p);  in main()
58     assert(fs.is_open());  in main()
59     fs << c;  in main()
62     std::wifstream fs(p.c_str());  in main()  local
64     fs >> c;  in main()