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The C and C++ Include Header Files
/usr/include/c++/11/bits/postypes.h
$ cat -n /usr/include/c++/11/bits/postypes.h 1 // Position types -*- C++ -*- 2 3 // Copyright (C) 1997-2021 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 /** @file bits/postypes.h 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{iosfwd} 28 */ 29 30 // 31 // ISO C++ 14882: 27.4.1 - Types 32 // ISO C++ 14882: 27.4.3 - Template class fpos 33 // 34 35 #ifndef _GLIBCXX_POSTYPES_H 36 #define _GLIBCXX_POSTYPES_H 1 37 38 #pragma GCC system_header 39 40 #include <cwchar> // For mbstate_t 41 42 // XXX If <stdint.h> is really needed, make sure to define the macros 43 // before including it, in order not to break <tr1/cstdint> (and <cstdint> 44 // in C++11). Reconsider all this as soon as possible... 45 #if (defined(_GLIBCXX_HAVE_INT64_T) && !defined(_GLIBCXX_HAVE_INT64_T_LONG) \ 46 && !defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG)) 47 48 #ifndef __STDC_LIMIT_MACROS 49 # define _UNDEF__STDC_LIMIT_MACROS 50 # define __STDC_LIMIT_MACROS 51 #endif 52 #ifndef __STDC_CONSTANT_MACROS 53 # define _UNDEF__STDC_CONSTANT_MACROS 54 # define __STDC_CONSTANT_MACROS 55 #endif 56 #include <stdint.h> // For int64_t 57 #ifdef _UNDEF__STDC_LIMIT_MACROS 58 # undef __STDC_LIMIT_MACROS 59 # undef _UNDEF__STDC_LIMIT_MACROS 60 #endif 61 #ifdef _UNDEF__STDC_CONSTANT_MACROS 62 # undef __STDC_CONSTANT_MACROS 63 # undef _UNDEF__STDC_CONSTANT_MACROS 64 #endif 65 66 #endif 67 68 namespace std _GLIBCXX_VISIBILITY(default) 69 { 70 _GLIBCXX_BEGIN_NAMESPACE_VERSION 71 72 // The types streamoff, streampos and wstreampos and the class 73 // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2, 74 // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the 75 // behaviour of these types is mostly implementation defined or 76 // unspecified. The behaviour in this implementation is as noted 77 // below. 78 79 /** 80 * @brief Type used by fpos, char_traits<char>, and char_traits<wchar_t>. 81 * 82 * In clauses 21.1.3.1 and 27.4.1 streamoff is described as an 83 * implementation defined type. 84 * Note: In versions of GCC up to and including GCC 3.3, streamoff 85 * was typedef long. 86 */ 87 #ifdef _GLIBCXX_HAVE_INT64_T_LONG 88 typedef long streamoff; 89 #elif defined(_GLIBCXX_HAVE_INT64_T_LONG_LONG) 90 typedef long long streamoff; 91 #elif defined(_GLIBCXX_HAVE_INT64_T) 92 typedef int64_t streamoff; 93 #else 94 typedef long long streamoff; 95 #endif 96 97 /// Integral type for I/O operation counts and buffer sizes. 98 typedef ptrdiff_t streamsize; // Signed integral type 99 100 /** 101 * @brief Class representing stream positions. 102 * 103 * The standard places no requirements upon the template parameter StateT. 104 * In this implementation StateT must be DefaultConstructible, 105 * CopyConstructible and Assignable. The standard only requires that fpos 106 * should contain a member of type StateT. In this implementation it also 107 * contains an offset stored as a signed integer. 108 * 109 * @param StateT Type passed to and returned from state(). 110 */ 111 template<typename _StateT> 112 class fpos 113 { 114 private: 115 streamoff _M_off; 116 _StateT _M_state; 117 118 public: 119 // The standard doesn't require that fpos objects can be default 120 // constructed. This implementation provides a default 121 // constructor that initializes the offset to 0 and default 122 // constructs the state. 123 fpos() 124 : _M_off(0), _M_state() { } 125 126 // The standard requires that fpos objects can be constructed 127 // from streamoff objects using the constructor syntax, and 128 // fails to give any meaningful semantics. In this 129 // implementation implicit conversion is also allowed, and this 130 // constructor stores the streamoff as the offset and default 131 // constructs the state. 132 /// Construct position from offset. 133 fpos(streamoff __off) 134 : _M_off(__off), _M_state() { } 135 136 #if __cplusplus >= 201103L 137 fpos(const fpos&) = default; 138 fpos& operator=(const fpos&) = default; 139 ~fpos() = default; 140 #endif 141 142 /// Convert to streamoff. 143 operator streamoff() const { return _M_off; } 144 145 /// Remember the value of @a st. 146 void 147 state(_StateT __st) 148 { _M_state = __st; } 149 150 /// Return the last set value of @a st. 151 _StateT 152 state() const 153 { return _M_state; } 154 155 // The standard requires that this operator must be defined, but 156 // gives no semantics. In this implementation it just adds its 157 // argument to the stored offset and returns *this. 158 /// Add offset to this position. 159 fpos& 160 operator+=(streamoff __off) 161 { 162 _M_off += __off; 163 return *this; 164 } 165 166 // The standard requires that this operator must be defined, but 167 // gives no semantics. In this implementation it just subtracts 168 // its argument from the stored offset and returns *this. 169 /// Subtract offset from this position. 170 fpos& 171 operator-=(streamoff __off) 172 { 173 _M_off -= __off; 174 return *this; 175 } 176 177 // The standard requires that this operator must be defined, but 178 // defines its semantics only in terms of operator-. In this 179 // implementation it constructs a copy of *this, adds the 180 // argument to that copy using operator+= and then returns the 181 // copy. 182 /// Add position and offset. 183 fpos 184 operator+(streamoff __off) const 185 { 186 fpos __pos(*this); 187 __pos += __off; 188 return __pos; 189 } 190 191 // The standard requires that this operator must be defined, but 192 // defines its semantics only in terms of operator+. In this 193 // implementation it constructs a copy of *this, subtracts the 194 // argument from that copy using operator-= and then returns the 195 // copy. 196 /// Subtract offset from position. 197 fpos 198 operator-(streamoff __off) const 199 { 200 fpos __pos(*this); 201 __pos -= __off; 202 return __pos; 203 } 204 205 // The standard requires that this operator must be defined, but 206 // defines its semantics only in terms of operator+. In this 207 // implementation it returns the difference between the offset 208 // stored in *this and in the argument. 209 /// Subtract position to return offset. 210 streamoff 211 operator-(const fpos& __other) const 212 { return _M_off - __other._M_off; } 213 }; 214 215 // The standard only requires that operator== must be an 216 // equivalence relation. In this implementation two fpos<StateT> 217 // objects belong to the same equivalence class if the contained 218 // offsets compare equal. 219 /// Test if equivalent to another position. 220 template<typename _StateT> 221 inline bool 222 operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 223 { return streamoff(__lhs) == streamoff(__rhs); } 224 225 template<typename _StateT> 226 inline bool 227 operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 228 { return streamoff(__lhs) != streamoff(__rhs); } 229 230 // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos 231 // as implementation defined types, but clause 27.2 requires that 232 // they must both be typedefs for fpos<mbstate_t> 233 /// File position for char streams. 234 typedef fpos<mbstate_t> streampos; 235 /// File position for wchar_t streams. 236 typedef fpos<mbstate_t> wstreampos; 237 238 #ifdef _GLIBCXX_USE_CHAR8_T 239 /// File position for char8_t streams. 240 typedef fpos<mbstate_t> u8streampos; 241 #endif 242 243 #if __cplusplus >= 201103L 244 /// File position for char16_t streams. 245 typedef fpos<mbstate_t> u16streampos; 246 /// File position for char32_t streams. 247 typedef fpos<mbstate_t> u32streampos; 248 #endif 249 250 _GLIBCXX_END_NAMESPACE_VERSION 251 } // namespace 252 253 #endif
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