27     : public std::ios
29     testios(std::streambuf* p) : std::ios(p) {}  in testios()
30     void set_rdbuf(std::streambuf* x) {std::ios::set_rdbuf(x);}  in set_rdbuf()
37     testios ios(&sb1);  in main()  local
41         ios.setstate(std::ios::badbit);  in main()
42         ios.exceptions(std::ios::badbit);  in main()
49     ios.set_rdbuf(&sb2);  in main()
50     assert(ios.rdbuf() == &sb2);  in main()
54         ios.setstate(std::ios::badbit);  in main()
55         ios.exceptions(std::ios::badbit);  in main()
61     ios.set_rdbuf(0);  in main()
62     assert(ios.rdbuf() == 0);  in main()