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      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_ofstream
     14 
     15 // template <class charT, class traits>
     16 //   void swap(basic_ofstream<charT, traits>& x, basic_ofstream<charT, traits>& y);
     17 
     18 #include <fstream>
     19 #include <utility>
     20 #include <cassert>
     21 #include "platform_support.h"
     22 
     23 std::pair<std::string, std::string> get_temp_file_names() {
     24   std::pair<std::string, std::string> names;
     25   names.first = get_temp_file_name();
     26 
     27   // Create the file so the next call to `get_temp_file_name()` doesn't
     28   // return the same file.
     29   std::FILE *fd1 = std::fopen(names.first.c_str(), "w");
     30 
     31   names.second = get_temp_file_name();
     32   assert(names.first != names.second);
     33 
     34   std::fclose(fd1);
     35   std::remove(names.first.c_str());
     36 
     37   return names;
     38 }
     39 
     40 int main()
     41 {
     42     std::pair<std::string, std::string> temp_files = get_temp_file_names();
     43     std::string& temp1 = temp_files.first;
     44     std::string& temp2 = temp_files.second;
     45     assert(temp1 != temp2);
     46     {
     47         std::ofstream fs1(temp1.c_str());
     48         std::ofstream fs2(temp2.c_str());
     49         fs1 << 3.25;
     50         fs2 << 4.5;
     51         swap(fs1, fs2);
     52         fs1 << ' ' << 3.25;
     53         fs2 << ' ' << 4.5;
     54     }
     55     {
     56         std::ifstream fs(temp1.c_str());
     57         double x = 0;
     58         fs >> x;
     59         assert(x == 3.25);
     60         fs >> x;
     61         assert(x == 4.5);
     62     }
     63     std::remove(temp1.c_str());
     64     {
     65         std::ifstream fs(temp2.c_str());
     66         double x = 0;
     67         fs >> x;
     68         assert(x == 4.5);
     69         fs >> x;
     70         assert(x == 3.25);
     71     }
     72     std::remove(temp2.c_str());
     73     {
     74         std::wofstream fs1(temp1.c_str());
     75         std::wofstream fs2(temp2.c_str());
     76         fs1 << 3.25;
     77         fs2 << 4.5;
     78         swap(fs1, fs2);
     79         fs1 << ' ' << 3.25;
     80         fs2 << ' ' << 4.5;
     81     }
     82     {
     83         std::wifstream fs(temp1.c_str());
     84         double x = 0;
     85         fs >> x;
     86         assert(x == 3.25);
     87         fs >> x;
     88         assert(x == 4.5);
     89     }
     90     std::remove(temp1.c_str());
     91     {
     92         std::wifstream fs(temp2.c_str());
     93         double x = 0;
     94         fs >> x;
     95         assert(x == 4.5);
     96         fs >> x;
     97         assert(x == 3.25);
     98     }
     99     std::remove(temp2.c_str());
    100 }
    101