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 // <ostream>
11 
12 // template <class charT, class traits = char_traits<charT> >
13 //   class basic_ostream;
14 
15 // basic_ostream& flush();
16 
17 #include <ostream>
18 #include <cassert>
19 
20 int sync_called = 0;
21 
22 template <class CharT>
23 class testbuf
24     : public std::basic_streambuf<CharT>
25 {
26 public:
testbuf()27     testbuf()
28     {
29     }
30 
31 protected:
32 
33     virtual int
sync()34         sync()
35         {
36             if (sync_called++ == 1)
37                 return -1;
38             return 0;
39         }
40 };
41 
main()42 int main()
43 {
44     {
45         testbuf<char> sb;
46         std::ostream os(&sb);
47         os.flush();
48         assert(os.good());
49         assert(sync_called == 1);
50         os.flush();
51         assert(os.bad());
52         assert(sync_called == 2);
53     }
54 }
55