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