1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <fstream>
11 
12 // int_type pbackfail(int_type c = traits::eof());
13 
14 // This test is not entirely portable
15 
16 #include <fstream>
17 #include <cassert>
18 
19 template <class CharT>
20 struct test_buf
21     : public std::basic_filebuf<CharT>
22 {
23     typedef std::basic_filebuf<CharT>  base;
24     typedef typename base::char_type   char_type;
25     typedef typename base::int_type    int_type;
26     typedef typename base::traits_type traits_type;
27 
ebacktest_buf28     char_type* eback() const {return base::eback();}
gptrtest_buf29     char_type* gptr()  const {return base::gptr();}
egptrtest_buf30     char_type* egptr() const {return base::egptr();}
gbumptest_buf31     void gbump(int n) {base::gbump(n);}
32 
pbackfailtest_buf33     virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);}
34 };
35 
main()36 int main()
37 {
38     {
39         test_buf<char> f;
40         assert(f.open("underflow.dat", std::ios_base::in) != 0);
41         assert(f.is_open());
42         assert(f.sbumpc() == '1');
43         assert(f.sgetc() == '2');
44         assert(f.pbackfail('a') == -1);
45     }
46     {
47         test_buf<char> f;
48         assert(f.open("underflow.dat", std::ios_base::in | std::ios_base::out) != 0);
49         assert(f.is_open());
50         assert(f.sbumpc() == '1');
51         assert(f.sgetc() == '2');
52         assert(f.pbackfail('a') == 'a');
53         assert(f.sbumpc() == 'a');
54         assert(f.sgetc() == '2');
55     }
56 }
57