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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 // void swap(basic_ofstream& rhs);
     16 
     17 #include <fstream>
     18 #include <utility>
     19 #include <cassert>
     20 #include "platform_support.h"
     21 
     22 std::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 
     39 int 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::ofstream fs1(temp1.c_str());
     47         std::ofstream fs2(temp2.c_str());
     48         fs1 << 3.25;
     49         fs2 << 4.5;
     50         fs1.swap(fs2);
     51         fs1 << ' ' << 3.25;
     52         fs2 << ' ' << 4.5;
     53     }
     54     {
     55         std::ifstream fs(temp1.c_str());
     56         double x = 0;
     57         fs >> x;
     58         assert(x == 3.25);
     59         fs >> x;
     60         assert(x == 4.5);
     61     }
     62     std::remove(temp1.c_str());
     63     {
     64         std::ifstream fs(temp2.c_str());
     65         double x = 0;
     66         fs >> x;
     67         assert(x == 4.5);
     68         fs >> x;
     69         assert(x == 3.25);
     70     }
     71     std::remove(temp2.c_str());
     72     {
     73         std::wofstream fs1(temp1.c_str());
     74         std::wofstream fs2(temp2.c_str());
     75         fs1 << 3.25;
     76         fs2 << 4.5;
     77         fs1.swap(fs2);
     78         fs1 << ' ' << 3.25;
     79         fs2 << ' ' << 4.5;
     80     }
     81     {
     82         std::wifstream fs(temp1.c_str());
     83         double x = 0;
     84         fs >> x;
     85         assert(x == 3.25);
     86         fs >> x;
     87         assert(x == 4.5);
     88     }
     89     std::remove(temp1.c_str());
     90     {
     91         std::wifstream fs(temp2.c_str());
     92         double x = 0;
     93         fs >> x;
     94         assert(x == 4.5);
     95         fs >> x;
     96         assert(x == 3.25);
     97     }
     98     std::remove(temp2.c_str());
     99 }
    100