Where Online Learning is simpler!
The C and C++ Include Header Files
cat -n /usr/include/c++/15/new
1 // The -*- C++ -*- dynamic memory management header. 2 3 // Copyright (C) 1994-2025 Free Software Foundation, Inc. 4 5 // This file is part of GCC. 6 // 7 // GCC is free software; you can redistribute it and/or modify 8 // it under the terms of the GNU General Public License as published by 9 // the Free Software Foundation; either version 3, or (at your option) 10 // any later version. 11 // 12 // GCC is distributed in the hope that it will be useful, 13 // but WITHOUT ANY WARRANTY; without even the implied warranty of 14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 // GNU General Public License for more details. 16 // 17 // Under Section 7 of GPL version 3, you are granted additional 18 // permissions described in the GCC Runtime Library Exception, version 19 // 3.1, as published by the Free Software Foundation. 20 21 // You should have received a copy of the GNU General Public License and 22 // a copy of the GCC Runtime Library Exception along with this program; 23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 // <http://www.gnu.org/licenses/>. 25 26 /** @file new 27 * This is a Standard C++ Library header. 28 * 29 * The header @c new defines several functions to manage dynamic memory and 30 * handling memory allocation errors; see 31 * https://gcc.gnu.org/onlinedocs/libstdc++/manual/dynamic_memory.html 32 * for more. 33 */ 34 35 #ifndef _NEW 36 #define _NEW 37 38 #ifdef _GLIBCXX_SYSHDR 39 #pragma GCC system_header 40 #endif 41 42 #include <bits/c++config.h> 43 #include <bits/exception.h> 44 45 #define __glibcxx_want_launder 46 #define __glibcxx_want_hardware_interference_size 47 #define __glibcxx_want_destroying_delete 48 #define __glibcxx_want_constexpr_new 49 #include <bits/version.h> 50 51 #pragma GCC diagnostic push 52 #pragma GCC diagnostic ignored "-Wc++11-extensions" // scoped enum 53 54 #pragma GCC visibility push(default) 55 56 extern "C++" { 57 58 namespace std 59 { 60 /** 61 * @brief Exception possibly thrown by @c new. 62 * @ingroup exceptions 63 * 64 * @c bad_alloc (or classes derived from it) is used to report allocation 65 * errors from the throwing forms of @c new. */ 66 class bad_alloc : public exception 67 { 68 public: 69 bad_alloc() throw() { } 70 71 #if __cplusplus >= 201103L 72 bad_alloc(const bad_alloc&) = default; 73 bad_alloc& operator=(const bad_alloc&) = default; 74 #endif 75 76 // This declaration is not useless: 77 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 78 virtual ~bad_alloc() throw(); 79 80 // See comment in eh_exception.cc. 81 virtual const char* what() const throw(); 82 }; 83 84 #if __cplusplus >= 201103L 85 class bad_array_new_length : public bad_alloc 86 { 87 public: 88 bad_array_new_length() throw() { } 89 90 // This declaration is not useless: 91 // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118 92 virtual ~bad_array_new_length() throw(); 93 94 // See comment in eh_exception.cc. 95 virtual const char* what() const throw(); 96 }; 97 #endif 98 99 #if __cpp_aligned_new 100 enum class align_val_t: size_t {}; 101 #endif 102 103 struct nothrow_t 104 { 105 #if __cplusplus >= 201103L 106 explicit nothrow_t() = default; 107 #endif 108 }; 109 110 extern const nothrow_t nothrow; 111 112 /** If you write your own error handler to be called by @c new, it must 113 * be of this type. */ 114 typedef void (*new_handler)(); 115 116 /// Takes a replacement handler as the argument, returns the 117 /// previous handler. 118 new_handler set_new_handler(new_handler) throw(); 119 120 #if __cplusplus >= 201103L 121 /// Return the current new handler. 122 new_handler get_new_handler() noexcept; 123 #endif 124 } // namespace std 125 126 //@{ 127 /** These are replaceable signatures: 128 * - normal single new and delete (no arguments, throw @c bad_alloc on error) 129 * - normal array new and delete (same) 130 * - @c nothrow single new and delete (take a @c nothrow argument, return 131 * @c NULL on error) 132 * - @c nothrow array new and delete (same) 133 * 134 * Placement new and delete signatures (take a memory address argument, 135 * does nothing) may not be replaced by a user's program. 136 */ 137 _GLIBCXX_NODISCARD void* operator new(std::size_t) 138 _GLIBCXX_TXN_SAFE _GLIBCXX_THROW (std::bad_alloc) 139 __attribute__((__externally_visible__, __malloc__)); 140 _GLIBCXX_NODISCARD void* operator new[](std::size_t) 141 _GLIBCXX_TXN_SAFE _GLIBCXX_THROW (std::bad_alloc) 142 __attribute__((__externally_visible__, __malloc__)); 143 void operator delete(void*) _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 144 __attribute__((__externally_visible__)); 145 void operator delete[](void*) _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 146 __attribute__((__externally_visible__)); 147 #if __cpp_sized_deallocation 148 void operator delete(void*, std::size_t) 149 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 150 __attribute__((__externally_visible__)); 151 void operator delete[](void*, std::size_t) 152 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 153 __attribute__((__externally_visible__)); 154 #endif 155 _GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&) 156 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 157 __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__)); 158 _GLIBCXX_NODISCARD void* operator new[](std::size_t, const std::nothrow_t&) 159 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 160 __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__)); 161 void operator delete(void*, const std::nothrow_t&) 162 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 163 __attribute__((__externally_visible__)); 164 void operator delete[](void*, const std::nothrow_t&) 165 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 166 __attribute__((__externally_visible__)); 167 #if __cpp_aligned_new 168 _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t) 169 _GLIBCXX_TXN_SAFE 170 __attribute__((__externally_visible__, __alloc_size__ (1), __alloc_align__ (2), __malloc__)); 171 _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t, const std::nothrow_t&) 172 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 173 __attribute__((__externally_visible__, __alloc_size__ (1), __alloc_align__ (2), __malloc__)); 174 void operator delete(void*, std::align_val_t) _GLIBCXX_TXN_SAFE 175 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__)); 176 void operator delete(void*, std::align_val_t, const std::nothrow_t&) 177 _GLIBCXX_TXN_SAFE 178 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__)); 179 _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t) 180 _GLIBCXX_TXN_SAFE 181 __attribute__((__externally_visible__, __alloc_size__ (1), __alloc_align__ (2), __malloc__)); 182 _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t, const std::nothrow_t&) 183 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 184 __attribute__((__externally_visible__, __alloc_size__ (1), __alloc_align__ (2), __malloc__)); 185 void operator delete[](void*, std::align_val_t) _GLIBCXX_TXN_SAFE 186 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__)); 187 void operator delete[](void*, std::align_val_t, const std::nothrow_t&) 188 _GLIBCXX_TXN_SAFE 189 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__)); 190 #if __cpp_sized_deallocation 191 void operator delete(void*, std::size_t, std::align_val_t) _GLIBCXX_TXN_SAFE 192 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__)); 193 void operator delete[](void*, std::size_t, std::align_val_t) _GLIBCXX_TXN_SAFE 194 _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__)); 195 #endif // __cpp_sized_deallocation 196 #endif // __cpp_aligned_new 197 198 #if __cpp_lib_constexpr_new >= 202406L 199 # define _GLIBCXX_PLACEMENT_CONSTEXPR constexpr 200 #else 201 # define _GLIBCXX_PLACEMENT_CONSTEXPR inline 202 #endif 203 204 // Default placement versions of operator new. 205 _GLIBCXX_NODISCARD _GLIBCXX_PLACEMENT_CONSTEXPR 206 void* operator new(std::size_t, void* __p) 207 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 208 { return __p; } 209 _GLIBCXX_NODISCARD _GLIBCXX_PLACEMENT_CONSTEXPR 210 void* operator new[](std::size_t, void* __p) 211 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 212 { return __p; } 213 214 #undef _GLIBCXX_PLACEMENT_CONSTEXPR 215 216 // Default placement versions of operator delete. 217 inline void operator delete (void*, void*) 218 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 219 { } 220 inline void operator delete[](void*, void*) 221 _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT 222 { } 223 //@} 224 } // extern "C++" 225 226 namespace std 227 { 228 #ifdef __cpp_lib_launder // C++ >= 17 && HAVE_BUILTIN_LAUNDER 229 /// Pointer optimization barrier [ptr.launder] 230 template<typename _Tp> 231 [[nodiscard]] constexpr _Tp* 232 launder(_Tp* __p) noexcept 233 { 234 if constexpr (__is_same(const volatile _Tp, const volatile void)) 235 static_assert(!__is_same(const volatile _Tp, const volatile void), 236 "std::launder argument must not be a void pointer"); 237 #if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function) 238 else if constexpr (__is_function(_Tp)) 239 static_assert(!__is_function(_Tp), 240 "std::launder argument must not be a function pointer"); 241 #endif 242 else 243 return __builtin_launder(__p); 244 return nullptr; 245 } 246 #endif // __cpp_lib_launder 247 248 #ifdef __cpp_lib_hardware_interference_size // C++ >= 17 && defined(gcc_dest_sz) 249 inline constexpr size_t hardware_destructive_interference_size = __GCC_DESTRUCTIVE_SIZE; 250 inline constexpr size_t hardware_constructive_interference_size = __GCC_CONSTRUCTIVE_SIZE; 251 #endif // __cpp_lib_hardware_interference_size 252 253 // Emitted despite the FTM potentially being undefined. 254 #if __cplusplus >= 202002L 255 /// Tag type used to declare a class-specific operator delete that can 256 /// invoke the destructor before deallocating the memory. 257 struct destroying_delete_t 258 { 259 explicit destroying_delete_t() = default; 260 }; 261 /// Tag variable of type destroying_delete_t. 262 inline constexpr destroying_delete_t destroying_delete{}; 263 #endif // C++20 264 } 265 266 #pragma GCC visibility pop 267 #pragma GCC diagnostic pop 268 269 #endif
