1// Iostreams base classes -*- C++ -*-
2
3// Copyright (C) 1997-2022 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25//
26// ISO C++ 14882: 27.4  Iostreams base classes
27//
28
29#include <ios>
30#include <ostream>
31#include <istream>
32#include <fstream>
33#include <ext/stdio_filebuf.h>
34#include <ext/stdio_sync_filebuf.h>
35
36namespace __gnu_internal _GLIBCXX_VISIBILITY(hidden)
37{
38  using namespace __gnu_cxx;
39
40  // Extern declarations for global objects in src/c++98/globals.cc.
41  extern stdio_sync_filebuf<char> buf_cout_sync;
42  extern stdio_sync_filebuf<char> buf_cin_sync;
43  extern stdio_sync_filebuf<char> buf_cerr_sync;
44
45  extern stdio_filebuf<char> buf_cout;
46  extern stdio_filebuf<char> buf_cin;
47  extern stdio_filebuf<char> buf_cerr;
48
49#ifdef _GLIBCXX_USE_WCHAR_T
50  extern stdio_sync_filebuf<wchar_t> buf_wcout_sync;
51  extern stdio_sync_filebuf<wchar_t> buf_wcin_sync;
52  extern stdio_sync_filebuf<wchar_t> buf_wcerr_sync;
53
54  extern stdio_filebuf<wchar_t> buf_wcout;
55  extern stdio_filebuf<wchar_t> buf_wcin;
56  extern stdio_filebuf<wchar_t> buf_wcerr;
57#endif
58} // namespace __gnu_internal
59
60namespace std _GLIBCXX_VISIBILITY(default)
61{
62_GLIBCXX_BEGIN_NAMESPACE_VERSION
63
64  using namespace __gnu_internal;
65
66  extern istream cin;
67  extern ostream cout;
68  extern ostream cerr;
69  extern ostream clog;
70
71#ifdef _GLIBCXX_USE_WCHAR_T
72  extern wistream wcin;
73  extern wostream wcout;
74  extern wostream wcerr;
75  extern wostream wclog;
76#endif
77
78  ios_base::Init::Init()
79  {
80    if (__gnu_cxx::__exchange_and_add_dispatch(&_S_refcount, 1) == 0)
81      {
82	// Standard streams default to synced with "C" operations.
83	_S_synced_with_stdio = true;
84
85	new (&buf_cout_sync) stdio_sync_filebuf<char>(stdout);
86	new (&buf_cin_sync) stdio_sync_filebuf<char>(stdin);
87	new (&buf_cerr_sync) stdio_sync_filebuf<char>(stderr);
88
89	// The standard streams are constructed once only and never
90	// destroyed.
91	new (&cout) ostream(&buf_cout_sync);
92	new (&cin) istream(&buf_cin_sync);
93	new (&cerr) ostream(&buf_cerr_sync);
94	new (&clog) ostream(&buf_cerr_sync);
95	cin.tie(&cout);
96	cerr.setf(ios_base::unitbuf);
97	// _GLIBCXX_RESOLVE_LIB_DEFECTS
98	// 455. cerr::tie() and wcerr::tie() are overspecified.
99	cerr.tie(&cout);
100
101#ifdef _GLIBCXX_USE_WCHAR_T
102	new (&buf_wcout_sync) stdio_sync_filebuf<wchar_t>(stdout);
103	new (&buf_wcin_sync) stdio_sync_filebuf<wchar_t>(stdin);
104	new (&buf_wcerr_sync) stdio_sync_filebuf<wchar_t>(stderr);
105
106	new (&wcout) wostream(&buf_wcout_sync);
107	new (&wcin) wistream(&buf_wcin_sync);
108	new (&wcerr) wostream(&buf_wcerr_sync);
109	new (&wclog) wostream(&buf_wcerr_sync);
110	wcin.tie(&wcout);
111	wcerr.setf(ios_base::unitbuf);
112	wcerr.tie(&wcout);
113#endif
114
115	// NB: Have to set refcount above one, so that standard
116	// streams are not re-initialized with uses of ios_base::Init
117	// besides <iostream> static object, ie just using <ios> with
118	// ios_base::Init objects.
119	__gnu_cxx::__atomic_add_dispatch(&_S_refcount, 1);
120      }
121  }
122
123  ios_base::Init::~Init()
124  {
125    // Be race-detector-friendly.  For more info see bits/c++config.
126    _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&_S_refcount);
127    if (__gnu_cxx::__exchange_and_add_dispatch(&_S_refcount, -1) == 2)
128      {
129        _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&_S_refcount);
130	// Catch any exceptions thrown by basic_ostream::flush()
131	__try
132	  {
133	    // Flush standard output streams as required by 27.4.2.1.6
134	    cout.flush();
135	    cerr.flush();
136	    clog.flush();
137
138#ifdef _GLIBCXX_USE_WCHAR_T
139	    wcout.flush();
140	    wcerr.flush();
141	    wclog.flush();
142#endif
143	  }
144	__catch(...)
145	  { }
146      }
147  }
148
149  bool
150  ios_base::sync_with_stdio(bool __sync)
151  {
152    // _GLIBCXX_RESOLVE_LIB_DEFECTS
153    // 49.  Underspecification of ios_base::sync_with_stdio
154    bool __ret = ios_base::Init::_S_synced_with_stdio;
155
156    // Turn off sync with C FILE* for cin, cout, cerr, clog iff
157    // currently synchronized.
158    if (!__sync && __ret)
159      {
160	// Make sure the standard streams are constructed.
161	ios_base::Init __init;
162
163	ios_base::Init::_S_synced_with_stdio = __sync;
164
165	// Explicitly call dtors to free any memory that is
166	// dynamically allocated by filebuf ctor or member functions,
167	// but don't deallocate all memory by calling operator delete.
168	buf_cout_sync.~stdio_sync_filebuf<char>();
169	buf_cin_sync.~stdio_sync_filebuf<char>();
170	buf_cerr_sync.~stdio_sync_filebuf<char>();
171
172#ifdef _GLIBCXX_USE_WCHAR_T
173	buf_wcout_sync.~stdio_sync_filebuf<wchar_t>();
174	buf_wcin_sync.~stdio_sync_filebuf<wchar_t>();
175	buf_wcerr_sync.~stdio_sync_filebuf<wchar_t>();
176#endif
177
178	// Create stream buffers for the standard streams and use
179	// those buffers without destroying and recreating the
180	// streams.
181	new (&buf_cout) stdio_filebuf<char>(stdout, ios_base::out);
182	new (&buf_cin) stdio_filebuf<char>(stdin, ios_base::in);
183	new (&buf_cerr) stdio_filebuf<char>(stderr, ios_base::out);
184	cout.rdbuf(&buf_cout);
185	cin.rdbuf(&buf_cin);
186	cerr.rdbuf(&buf_cerr);
187	clog.rdbuf(&buf_cerr);
188
189#ifdef _GLIBCXX_USE_WCHAR_T
190	new (&buf_wcout) stdio_filebuf<wchar_t>(stdout, ios_base::out);
191	new (&buf_wcin) stdio_filebuf<wchar_t>(stdin, ios_base::in);
192	new (&buf_wcerr) stdio_filebuf<wchar_t>(stderr, ios_base::out);
193	wcout.rdbuf(&buf_wcout);
194	wcin.rdbuf(&buf_wcin);
195	wcerr.rdbuf(&buf_wcerr);
196	wclog.rdbuf(&buf_wcerr);
197#endif
198      }
199    return __ret;
200  }
201
202_GLIBCXX_END_NAMESPACE_VERSION
203} // namespace
204