libstdc++-v3/src/ios_init.cc

   1 // Iostreams base classes -*- C++ -*-
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   4 // 2006, 2007, 2008, 2009, 2010, 2011
   5 // Free Software Foundation, Inc.
   6 //
   7 // This file is part of the GNU ISO C++ Library.  This library is free
   8 // software; you can redistribute it and/or modify it under the
   9 // terms of the GNU General Public License as published by the
  10 // Free Software Foundation; either version 3, or (at your option)
  11 // any later version.
  12
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // Under Section 7 of GPL version 3, you are granted additional
  19 // permissions described in the GCC Runtime Library Exception, version
  20 // 3.1, as published by the Free Software Foundation.
  21
  22 // You should have received a copy of the GNU General Public License and
  23 // a copy of the GCC Runtime Library Exception along with this program;
  24 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 // <http://www.gnu.org/licenses/>.
  26
  27 //
  28 // ISO C++ 14882: 27.4  Iostreams base classes
  29 //
  30
  31 #include <ios>
  32 #include <ostream>
  33 #include <istream>
  34 #include <fstream>
  35 #include <ext/stdio_filebuf.h>
  36 #include <ext/stdio_sync_filebuf.h>
  37
  38 namespace __gnu_internal _GLIBCXX_VISIBILITY(hidden)
  39 {
  40   using namespace __gnu_cxx;
  41
  42   // Extern declarations for global objects in src/globals.cc.
  43   extern stdio_sync_filebuf<char> buf_cout_sync;
  44   extern stdio_sync_filebuf<char> buf_cin_sync;
  45   extern stdio_sync_filebuf<char> buf_cerr_sync;
  46
  47   extern stdio_filebuf<char> buf_cout;
  48   extern stdio_filebuf<char> buf_cin;
  49   extern stdio_filebuf<char> buf_cerr;
  50
  51 #ifdef _GLIBCXX_USE_WCHAR_T
  52   extern stdio_sync_filebuf<wchar_t> buf_wcout_sync;
  53   extern stdio_sync_filebuf<wchar_t> buf_wcin_sync;
  54   extern stdio_sync_filebuf<wchar_t> buf_wcerr_sync;
  55
  56   extern stdio_filebuf<wchar_t> buf_wcout;
  57   extern stdio_filebuf<wchar_t> buf_wcin;
  58   extern stdio_filebuf<wchar_t> buf_wcerr;
  59 #endif
  60 } // namespace __gnu_internal
  61
  62 namespace std _GLIBCXX_VISIBILITY(default)
  63 {
  64 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  65
  66   using namespace __gnu_internal;
  67
  68   extern istream cin;
  69   extern ostream cout;
  70   extern ostream cerr;
  71   extern ostream clog;
  72
  73 #ifdef _GLIBCXX_USE_WCHAR_T
  74   extern wistream wcin;
  75   extern wostream wcout;
  76   extern wostream wcerr;
  77   extern wostream wclog;
  78 #endif
  79
  80   ios_base::Init::Init()
  81   {
  82     if (__gnu_cxx::__exchange_and_add_dispatch(&_S_refcount, 1) == 0)
  83       {
  84         // Standard streams default to synced with "C" operations.
  85         _S_synced_with_stdio = true;
  86
  87         new (&buf_cout_sync) stdio_sync_filebuf<char>(stdout);
  88         new (&buf_cin_sync) stdio_sync_filebuf<char>(stdin);
  89         new (&buf_cerr_sync) stdio_sync_filebuf<char>(stderr);
  90
  91         // The standard streams are constructed once only and never
  92         // destroyed.
  93         new (&cout) ostream(&buf_cout_sync);
  94         new (&cin) istream(&buf_cin_sync);
  95         new (&cerr) ostream(&buf_cerr_sync);
  96         new (&clog) ostream(&buf_cerr_sync);
  97         cin.tie(&cout);
  98         cerr.setf(ios_base::unitbuf);
  99         // _GLIBCXX_RESOLVE_LIB_DEFECTS
 100         // 455. cerr::tie() and wcerr::tie() are overspecified.
 101         cerr.tie(&cout);
 102
 103 #ifdef _GLIBCXX_USE_WCHAR_T
 104         new (&buf_wcout_sync) stdio_sync_filebuf<wchar_t>(stdout);
 105         new (&buf_wcin_sync) stdio_sync_filebuf<wchar_t>(stdin);
 106         new (&buf_wcerr_sync) stdio_sync_filebuf<wchar_t>(stderr);
 107
 108         new (&wcout) wostream(&buf_wcout_sync);
 109         new (&wcin) wistream(&buf_wcin_sync);
 110         new (&wcerr) wostream(&buf_wcerr_sync);
 111         new (&wclog) wostream(&buf_wcerr_sync);
 112         wcin.tie(&wcout);
 113         wcerr.setf(ios_base::unitbuf);
 114         wcerr.tie(&wcout);
 115 #endif
 116
 117         // NB: Have to set refcount above one, so that standard
 118         // streams are not re-initialized with uses of ios_base::Init
 119         // besides <iostream> static object, ie just using <ios> with
 120         // ios_base::Init objects.
 121         __gnu_cxx::__atomic_add_dispatch(&_S_refcount, 1);
 122       }
 123   }
 124
 125   ios_base::Init::~Init()
 126   {
 127     // Be race-detector-friendly.  For more info see bits/c++config.
 128     _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_S_refcount);
 129     if (__gnu_cxx::__exchange_and_add_dispatch(&_S_refcount, -1) == 2)
 130       {
 131         _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_S_refcount);
 132         // Catch any exceptions thrown by basic_ostream::flush()
 133         __try
 134           {
 135             // Flush standard output streams as required by 27.4.2.1.6
 136             cout.flush();
 137             cerr.flush();
 138             clog.flush();
 139
 140 #ifdef _GLIBCXX_USE_WCHAR_T
 141             wcout.flush();
 142             wcerr.flush();
 143             wclog.flush();
 144 #endif
 145           }
 146         __catch(...)
 147           { }
 148       }
 149   }
 150
 151   bool
 152   ios_base::sync_with_stdio(bool __sync)
 153   {
 154     // _GLIBCXX_RESOLVE_LIB_DEFECTS
 155     // 49.  Underspecification of ios_base::sync_with_stdio
 156     bool __ret = ios_base::Init::_S_synced_with_stdio;
 157
 158     // Turn off sync with C FILE* for cin, cout, cerr, clog iff
 159     // currently synchronized.
 160     if (!__sync && __ret)
 161       {
 162         // Make sure the standard streams are constructed.
 163         ios_base::Init __init;
 164
 165         ios_base::Init::_S_synced_with_stdio = __sync;
 166
 167         // Explicitly call dtors to free any memory that is
 168         // dynamically allocated by filebuf ctor or member functions,
 169         // but don't deallocate all memory by calling operator delete.
 170         buf_cout_sync.~stdio_sync_filebuf<char>();
 171         buf_cin_sync.~stdio_sync_filebuf<char>();
 172         buf_cerr_sync.~stdio_sync_filebuf<char>();
 173
 174 #ifdef _GLIBCXX_USE_WCHAR_T
 175         buf_wcout_sync.~stdio_sync_filebuf<wchar_t>();
 176         buf_wcin_sync.~stdio_sync_filebuf<wchar_t>();
 177         buf_wcerr_sync.~stdio_sync_filebuf<wchar_t>();
 178 #endif
 179
 180         // Create stream buffers for the standard streams and use
 181         // those buffers without destroying and recreating the
 182         // streams.
 183         new (&buf_cout) stdio_filebuf<char>(stdout, ios_base::out);
 184         new (&buf_cin) stdio_filebuf<char>(stdin, ios_base::in);
 185         new (&buf_cerr) stdio_filebuf<char>(stderr, ios_base::out);
 186         cout.rdbuf(&buf_cout);
 187         cin.rdbuf(&buf_cin);
 188         cerr.rdbuf(&buf_cerr);
 189         clog.rdbuf(&buf_cerr);
 190
 191 #ifdef _GLIBCXX_USE_WCHAR_T
 192         new (&buf_wcout) stdio_filebuf<wchar_t>(stdout, ios_base::out);
 193         new (&buf_wcin) stdio_filebuf<wchar_t>(stdin, ios_base::in);
 194         new (&buf_wcerr) stdio_filebuf<wchar_t>(stderr, ios_base::out);
 195         wcout.rdbuf(&buf_wcout);
 196         wcin.rdbuf(&buf_wcin);
 197         wcerr.rdbuf(&buf_wcerr);
 198         wclog.rdbuf(&buf_wcerr);
 199 #endif
 200       }
 201     return __ret;
 202   }
 203
 204 _GLIBCXX_END_NAMESPACE_VERSION
 205 } // namespace