libstdc++-v3/testsuite/27_io/filesystem/operations/resize_file.cc

   1 // Copyright (C) 2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19 // { dg-do run { target c++17 } }
  20 // { dg-require-filesystem-ts "" }
  21
  22 // C++17 30.10.15.33 Resize file [fs.op.resize_file]
  23
  24 #include <filesystem>
  25 #include <string>
  26 #include <fstream>
  27 #include <testsuite_fs.h>
  28 #include <testsuite_hooks.h>
  29
  30 void
  31 test01()
  32 {
  33   auto p = __gnu_test::nonexistent_path();
  34   std::error_code ec;
  35   resize_file(p, 0, ec);
  36   VERIFY( ec );
  37   ec = {};
  38   resize_file(p, 1, ec);
  39   VERIFY( ec );
  40
  41   __gnu_test::scoped_file f(p);
  42   std::ofstream{p} << "some text";
  43   std::ifstream fin;
  44   std::string input;
  45
  46 #ifdef _GLIBCXX_HAVE_TRUNCATE
  47   resize_file(p, 4, ec);
  48   VERIFY( !ec );
  49   fin.open(p);
  50   getline(fin, input);
  51   VERIFY( input.length() == 4 );
  52   fin.close();
  53
  54   resize_file(p, 2);
  55   fin.open(p);
  56   getline(fin, input);
  57   VERIFY( input.length() == 2 );
  58   fin.close();
  59 #endif
  60
  61   resize_file(p, 0, ec);
  62   VERIFY( !ec );
  63   fin.open(p);
  64   getline(fin, input);
  65   VERIFY( input.length() == 0 );
  66   fin.close();
  67 }
  68
  69 int
  70 main()
  71 {
  72   test01();
  73 }