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The C and C++ Include Header Files
cat -n /usr/include/c++/15/bits/postypes.h
1 // Position types -*- C++ -*- 2 3 // Copyright (C) 1997-2025 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 #ifdef _GLIBCXX_SYSHDR 39 #pragma GCC system_header 40 #endif 41 42 #include <cwchar> // For mbstate_t 43 44 namespace std _GLIBCXX_VISIBILITY(default) 45 { 46 _GLIBCXX_BEGIN_NAMESPACE_VERSION 47 48 // The types streamoff, streampos and wstreampos and the class 49 // template fpos<> are described in clauses 21.1.2, 21.1.3, 27.1.2, 50 // 27.2, 27.4.1, 27.4.3 and D.6. Despite all this verbiage, the 51 // behaviour of these types is mostly implementation defined or 52 // unspecified. The behaviour in this implementation is as noted 53 // below. 54 55 #pragma GCC diagnostic push 56 #pragma GCC diagnostic ignored "-Wlong-long" 57 /** 58 * @brief Type used by fpos, char_traits<char>, and char_traits<wchar_t>. 59 * 60 * In clauses 21.1.3.1 and 27.4.1 streamoff is described as an 61 * implementation defined type. 62 * Note: In versions of GCC up to and including GCC 3.3, streamoff 63 * was typedef long. 64 */ 65 #ifdef __INT64_TYPE__ 66 typedef __INT64_TYPE__ streamoff; 67 #else 68 typedef long long streamoff; 69 #endif 70 #pragma GCC diagnostic pop 71 72 /// Integral type for I/O operation counts and buffer sizes. 73 typedef ptrdiff_t streamsize; // Signed integral type 74 75 /** 76 * @brief Class representing stream positions. 77 * 78 * The standard places no requirements upon the template parameter StateT. 79 * In this implementation StateT must be DefaultConstructible, 80 * CopyConstructible and Assignable. The standard only requires that fpos 81 * should contain a member of type StateT. In this implementation it also 82 * contains an offset stored as a signed integer. 83 * 84 * @param StateT Type passed to and returned from state(). 85 */ 86 template<typename _StateT> 87 class fpos 88 { 89 private: 90 streamoff _M_off; 91 _StateT _M_state; 92 93 public: 94 // The standard doesn't require that fpos objects can be default 95 // constructed. This implementation provides a default 96 // constructor that initializes the offset to 0 and default 97 // constructs the state. 98 fpos() 99 : _M_off(0), _M_state() { } 100 101 // The standard requires that fpos objects can be constructed 102 // from streamoff objects using the constructor syntax, and 103 // fails to give any meaningful semantics. In this 104 // implementation implicit conversion is also allowed, and this 105 // constructor stores the streamoff as the offset and default 106 // constructs the state. 107 /// Construct position from offset. 108 fpos(streamoff __off) 109 : _M_off(__off), _M_state() { } 110 111 #if __cplusplus >= 201103L 112 fpos(const fpos&) = default; 113 fpos& operator=(const fpos&) = default; 114 ~fpos() = default; 115 #endif 116 117 /// Convert to streamoff. 118 operator streamoff() const { return _M_off; } 119 120 /// Remember the value of @a st. 121 void 122 state(_StateT __st) 123 { _M_state = __st; } 124 125 /// Return the last set value of @a st. 126 _StateT 127 state() const 128 { return _M_state; } 129 130 // The standard requires that this operator must be defined, but 131 // gives no semantics. In this implementation it just adds its 132 // argument to the stored offset and returns *this. 133 /// Add offset to this position. 134 fpos& 135 operator+=(streamoff __off) 136 { 137 _M_off += __off; 138 return *this; 139 } 140 141 // The standard requires that this operator must be defined, but 142 // gives no semantics. In this implementation it just subtracts 143 // its argument from the stored offset and returns *this. 144 /// Subtract offset from this position. 145 fpos& 146 operator-=(streamoff __off) 147 { 148 _M_off -= __off; 149 return *this; 150 } 151 152 // The standard requires that this operator must be defined, but 153 // defines its semantics only in terms of operator-. In this 154 // implementation it constructs a copy of *this, adds the 155 // argument to that copy using operator+= and then returns the 156 // copy. 157 /// Add position and offset. 158 fpos 159 operator+(streamoff __off) const 160 { 161 fpos __pos(*this); 162 __pos += __off; 163 return __pos; 164 } 165 166 // The standard requires that this operator must be defined, but 167 // defines its semantics only in terms of operator+. In this 168 // implementation it constructs a copy of *this, subtracts the 169 // argument from that copy using operator-= and then returns the 170 // copy. 171 /// Subtract offset from position. 172 fpos 173 operator-(streamoff __off) const 174 { 175 fpos __pos(*this); 176 __pos -= __off; 177 return __pos; 178 } 179 180 // The standard requires that this operator must be defined, but 181 // defines its semantics only in terms of operator+. In this 182 // implementation it returns the difference between the offset 183 // stored in *this and in the argument. 184 /// Subtract position to return offset. 185 streamoff 186 operator-(const fpos& __other) const 187 { return _M_off - __other._M_off; } 188 }; 189 190 // The standard only requires that operator== must be an 191 // equivalence relation. In this implementation two fpos<StateT> 192 // objects belong to the same equivalence class if the contained 193 // offsets compare equal. 194 /// Test if equivalent to another position. 195 template<typename _StateT> 196 inline bool 197 operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 198 { return streamoff(__lhs) == streamoff(__rhs); } 199 200 template<typename _StateT> 201 inline bool 202 operator!=(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs) 203 { return streamoff(__lhs) != streamoff(__rhs); } 204 205 // Clauses 21.1.3.1 and 21.1.3.2 describe streampos and wstreampos 206 // as implementation defined types, but clause 27.2 requires that 207 // they must both be typedefs for fpos<mbstate_t> 208 /// File position for char streams. 209 typedef fpos<mbstate_t> streampos; 210 /// File position for wchar_t streams. 211 typedef fpos<mbstate_t> wstreampos; 212 213 #ifdef _GLIBCXX_USE_CHAR8_T 214 /// File position for char8_t streams. 215 typedef fpos<mbstate_t> u8streampos; 216 #endif 217 218 #if __cplusplus >= 201103L 219 /// File position for char16_t streams. 220 typedef fpos<mbstate_t> u16streampos; 221 /// File position for char32_t streams. 222 typedef fpos<mbstate_t> u32streampos; 223 #endif 224 225 _GLIBCXX_END_NAMESPACE_VERSION 226 } // namespace 227 228 #endif
