libstdc++-v3/testsuite/performance/27_io/filebuf_sputn_unbuf.cc

// Copyright (C) 2004-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3.  If not see
// <http://www.gnu.org/licenses/>.

#include <unistd.h>
#include <cstdio>
#include <fstream>
#include <testsuite_performance.h>

// libstdc++/11378
int main()
{
  using namespace std;
  using namespace __gnu_test;

  time_counter time;
  resource_counter resource;

  const int iterations = 500000;
  const int chunksize = 100;

  char* chunk = new char[chunksize];

  // C
  FILE* file = fopen("tmp", "w+");
  setvbuf(file, 0, _IONBF, 0);
  start_counters(time, resource);
  for (int i = 0; i < iterations; ++i)
    fwrite(chunk, 1, chunksize, file);
  stop_counters(time, resource);
  fclose(file);
  report_performance(__FILE__, "C", time, resource);
  clear_counters(time, resource);

  // C unlocked
  file = fopen("tmp", "w+");
  setvbuf(file, 0, _IONBF, 0);
  start_counters(time, resource);
  for (int i = 0; i < iterations; ++i)
    fwrite_unlocked(chunk, 1, chunksize, file);
  stop_counters(time, resource);
  fclose(file);
  report_performance(__FILE__, "C unlocked", time, resource);
  clear_counters(time, resource);

  // C++
  filebuf buf;
  buf.pubsetbuf(0, 0);
  buf.open("tmp", ios_base::out | ios_base::in | ios_base::trunc);
  start_counters(time, resource);
  for (int i = 0; i < iterations; ++i)
    buf.sputn(chunk, chunksize);
  stop_counters(time, resource);
  report_performance(__FILE__, "C++", time, resource);

  unlink("tmp");
  delete [] chunk;

  return 0;
}