libstdc++-v3/testsuite/27_io/basic_filebuf/sgetn/char/81395.cc

   1 // Copyright (C) 2017-2020 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-require-fileio "" }
  19
  20 // PR libstdc++/81395
  21
  22 #include <fstream>
  23 #include <cstring>      // for std::memset
  24 #include <cstdio>       // For BUFSIZ
  25
  26 using std::memset;
  27
  28 int main()
  29 {
  30   {
  31     std::filebuf fb;
  32     fb.open("test.txt", std::ios::out);
  33     char data[BUFSIZ];
  34     memset(data, 'A', sizeof(data));
  35     fb.sputn(data, sizeof(data));
  36   }
  37
  38   std::filebuf fb;
  39   fb.open("test.txt", std::ios::in|std::ios::out);
  40   char buf[BUFSIZ];
  41   memset(buf, 0, sizeof(buf));
  42   fb.sgetn(buf, sizeof(buf));
  43   // Switch from reading to writing without seeking first:
  44   fb.sputn("B", 1);
  45   fb.pubsync();
  46 }