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 // template <class charT, class traits = char_traits<charT> >
13 // class basic_fstream
14 
15 // template <class charT, class traits>
16 //   void swap(basic_fstream<charT, traits>& x, basic_fstream<charT, traits>& y);
17 
18 #include <fstream>
19 #include <utility>
20 #include <cassert>
21 #include "platform_support.h"
22 
23 
get_temp_file_names()24 std::pair<std::string, std::string> get_temp_file_names() {
25   std::pair<std::string, std::string> names;
26   names.first = get_temp_file_name();
27 
28   // Create the file so the next call to `get_temp_file_name()` doesn't
29   // return the same file.
30   std::FILE *fd1 = std::fopen(names.first.c_str(), "w");
31 
32   names.second = get_temp_file_name();
33   assert(names.first != names.second);
34 
35   std::fclose(fd1);
36   std::remove(names.first.c_str());
37 
38   return names;
39 }
40 
main()41 int main()
42 {
43     std::pair<std::string, std::string> temp_files = get_temp_file_names();
44     std::string& temp1 = temp_files.first;
45     std::string& temp2 = temp_files.second;
46     assert(temp1 != temp2);
47     {
48         std::fstream fs1(temp1.c_str(), std::ios_base::in | std::ios_base::out
49                                                   | std::ios_base::trunc);
50         std::fstream fs2(temp2.c_str(), std::ios_base::in | std::ios_base::out
51                                                   | std::ios_base::trunc);
52         fs1 << 1 << ' ' << 2;
53         fs2 << 2 << ' ' << 1;
54         fs1.seekg(0);
55         swap(fs1, fs2);
56         fs1.seekg(0);
57         int i;
58         fs1 >> i;
59         assert(i == 2);
60         fs1 >> i;
61         assert(i == 1);
62         i = 0;
63         fs2 >> i;
64         assert(i == 1);
65         fs2 >> i;
66         assert(i == 2);
67     }
68     std::remove(temp1.c_str());
69     std::remove(temp2.c_str());
70     {
71         std::wfstream fs1(temp1.c_str(), std::ios_base::in | std::ios_base::out
72                                                    | std::ios_base::trunc);
73         std::wfstream fs2(temp2.c_str(), std::ios_base::in | std::ios_base::out
74                                                    | std::ios_base::trunc);
75         fs1 << 1 << ' ' << 2;
76         fs2 << 2 << ' ' << 1;
77         fs1.seekg(0);
78         swap(fs1, fs2);
79         fs1.seekg(0);
80         int i;
81         fs1 >> i;
82         assert(i == 2);
83         fs1 >> i;
84         assert(i == 1);
85         i = 0;
86         fs2 >> i;
87         assert(i == 1);
88         fs2 >> i;
89         assert(i == 2);
90     }
91     std::remove(temp1.c_str());
92     std::remove(temp2.c_str());
93 }
94