1 // ABI Support -*- C++ -*- 2 3 // Copyright (C) 2000-2021 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 // Written by Nathan Sidwell, Codesourcery LLC, <nathan@codesourcery.com> 27 28 /* This file declares the new abi entry points into the runtime. It is not 29 normally necessary for user programs to include this header, or use the 30 entry points directly. However, this header is available should that be 31 needed. 32 33 Some of the entry points are intended for both C and C++, thus this header 34 is includable from both C and C++. Though the C++ specific parts are not 35 available in C, naturally enough. */ 36 37 /** @file cxxabi.h 38 * The header provides an interface to the C++ ABI. 39 */ 40 41 #ifndef _CXXABI_H 42 #define _CXXABI_H 1 43 44 #pragma GCC system_header 45 46 #pragma GCC visibility push(default) 47 48 #include <stddef.h> 49 #include <bits/c++config.h> 50 #include <bits/cxxabi_tweaks.h> 51 #include <bits/cxxabi_forced.h> 52 #include <bits/cxxabi_init_exception.h> 53 54 #ifdef __cplusplus 55 namespace __cxxabiv1 56 { 57 extern "C" 58 { 59 #endif 60 61 typedef __cxa_cdtor_return_type (*__cxa_cdtor_type)(void *); 62 63 // Allocate array. 64 void* 65 __cxa_vec_new(size_t __element_count, size_t __element_size, 66 size_t __padding_size, __cxa_cdtor_type __constructor, 67 __cxa_cdtor_type __destructor); 68 69 void* 70 __cxa_vec_new2(size_t __element_count, size_t __element_size, 71 size_t __padding_size, __cxa_cdtor_type __constructor, 72 __cxa_cdtor_type __destructor, void *(*__alloc) (size_t), 73 void (*__dealloc) (void*)); 74 75 void* 76 __cxa_vec_new3(size_t __element_count, size_t __element_size, 77 size_t __padding_size, __cxa_cdtor_type __constructor, 78 __cxa_cdtor_type __destructor, void *(*__alloc) (size_t), 79 void (*__dealloc) (void*, size_t)); 80 81 // Construct array. 82 __cxa_vec_ctor_return_type 83 __cxa_vec_ctor(void* __array_address, size_t __element_count, 84 size_t __element_size, __cxa_cdtor_type __constructor, 85 __cxa_cdtor_type __destructor); 86 87 __cxa_vec_ctor_return_type 88 __cxa_vec_cctor(void* __dest_array, void* __src_array, 89 size_t __element_count, size_t __element_size, 90 __cxa_cdtor_return_type (*__constructor) (void*, void*), 91 __cxa_cdtor_type __destructor); 92 93 // Destruct array. 94 void 95 __cxa_vec_dtor(void* __array_address, size_t __element_count, 96 size_t __element_size, __cxa_cdtor_type __destructor); 97 98 void 99 __cxa_vec_cleanup(void* __array_address, size_t __element_count, size_t __s, 100 __cxa_cdtor_type __destructor) _GLIBCXX_NOTHROW; 101 102 // Destruct and release array. 103 void 104 __cxa_vec_delete(void* __array_address, size_t __element_size, 105 size_t __padding_size, __cxa_cdtor_type __destructor); 106 107 void 108 __cxa_vec_delete2(void* __array_address, size_t __element_size, 109 size_t __padding_size, __cxa_cdtor_type __destructor, 110 void (*__dealloc) (void*)); 111 112 void 113 __cxa_vec_delete3(void* __array_address, size_t __element_size, 114 size_t __padding_size, __cxa_cdtor_type __destructor, 115 void (*__dealloc) (void*, size_t)); 116 117 int 118 __cxa_guard_acquire(__guard*); 119 120 void 121 __cxa_guard_release(__guard*) _GLIBCXX_NOTHROW; 122 123 void 124 __cxa_guard_abort(__guard*) _GLIBCXX_NOTHROW; 125 126 // DSO destruction. 127 int 128 #ifdef _GLIBCXX_CDTOR_CALLABI 129 __cxa_atexit(void (_GLIBCXX_CDTOR_CALLABI *)(void*), void*, void*) _GLIBCXX_NOTHROW; 130 #else 131 __cxa_atexit(void (*)(void*), void*, void*) _GLIBCXX_NOTHROW; 132 #endif 133 134 void 135 __cxa_finalize(void*); 136 137 // TLS destruction. 138 int 139 #ifdef _GLIBCXX_CDTOR_CALLABI 140 __cxa_thread_atexit(void (_GLIBCXX_CDTOR_CALLABI *)(void*), void*, void *) _GLIBCXX_NOTHROW; 141 #else 142 __cxa_thread_atexit(void (*)(void*), void*, void *) _GLIBCXX_NOTHROW; 143 #endif 144 145 // Pure virtual functions. 146 void 147 __cxa_pure_virtual(void) __attribute__ ((__noreturn__)); 148 149 void 150 __cxa_deleted_virtual(void) __attribute__ ((__noreturn__)); 151 152 // Exception handling auxiliary. 153 void 154 __cxa_bad_cast() __attribute__((__noreturn__)); 155 156 void 157 __cxa_bad_typeid() __attribute__((__noreturn__)); 158 159 void 160 __cxa_throw_bad_array_new_length() __attribute__((__noreturn__)); 161 162 /** 163 * @brief Demangling routine. 164 * ABI-mandated entry point in the C++ runtime library for demangling. 165 * 166 * @param __mangled_name A NUL-terminated character string 167 * containing the name to be demangled. 168 * 169 * @param __output_buffer A region of memory, allocated with 170 * malloc, of @a *__length bytes, into which the demangled name is 171 * stored. If @a __output_buffer is not long enough, it is 172 * expanded using realloc. @a __output_buffer may instead be NULL; 173 * in that case, the demangled name is placed in a region of memory 174 * allocated with malloc. 175 * 176 * @param __length If @a __length is non-null, the length of the 177 * buffer containing the demangled name is placed in @a *__length. 178 * 179 * @param __status If @a __status is non-null, @a *__status is set to 180 * one of the following values: 181 * 0: The demangling operation succeeded. 182 * -1: A memory allocation failure occurred. 183 * -2: @a mangled_name is not a valid name under the C++ ABI mangling rules. 184 * -3: One of the arguments is invalid. 185 * 186 * @return A pointer to the start of the NUL-terminated demangled 187 * name, or NULL if the demangling fails. The caller is 188 * responsible for deallocating this memory using @c free. 189 * 190 * The demangling is performed using the C++ ABI mangling rules, 191 * with GNU extensions. For example, this function is used in 192 * __gnu_cxx::__verbose_terminate_handler. 193 * 194 * See https://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_demangling.html 195 * for other examples of use. 196 * 197 * @note The same demangling functionality is available via 198 * libiberty (@c <libiberty/demangle.h> and @c libiberty.a) in GCC 199 * 3.1 and later, but that requires explicit installation (@c 200 * --enable-install-libiberty) and uses a different API, although 201 * the ABI is unchanged. 202 */ 203 char* 204 __cxa_demangle(const char* __mangled_name, char* __output_buffer, 205 size_t* __length, int* __status); 206 207 #ifdef __cplusplus 208 } 209 } // namespace __cxxabiv1 210 #endif 211 212 #ifdef __cplusplus 213 214 #include <typeinfo> 215 216 namespace __cxxabiv1 217 { 218 // Type information for int, float etc. 219 class __fundamental_type_info : public std::type_info 220 { 221 public: 222 explicit __fundamental_type_info(const char * __n)223 __fundamental_type_info(const char* __n) : std::type_info(__n) { } 224 225 virtual 226 ~__fundamental_type_info(); 227 }; 228 229 // Type information for array objects. 230 class __array_type_info : public std::type_info 231 { 232 public: 233 explicit __array_type_info(const char * __n)234 __array_type_info(const char* __n) : std::type_info(__n) { } 235 236 virtual 237 ~__array_type_info(); 238 }; 239 240 // Type information for functions (both member and non-member). 241 class __function_type_info : public std::type_info 242 { 243 public: 244 explicit __function_type_info(const char * __n)245 __function_type_info(const char* __n) : std::type_info(__n) { } 246 247 virtual 248 ~__function_type_info(); 249 250 protected: 251 // Implementation defined member function. 252 virtual bool 253 __is_function_p() const; 254 }; 255 256 // Type information for enumerations. 257 class __enum_type_info : public std::type_info 258 { 259 public: 260 explicit __enum_type_info(const char * __n)261 __enum_type_info(const char* __n) : std::type_info(__n) { } 262 263 virtual 264 ~__enum_type_info(); 265 }; 266 267 // Common type information for simple pointers and pointers to member. 268 class __pbase_type_info : public std::type_info 269 { 270 public: 271 unsigned int __flags; // Qualification of the target object. 272 const std::type_info* __pointee; // Type of pointed to object. 273 274 explicit __pbase_type_info(const char * __n,int __quals,const std::type_info * __type)275 __pbase_type_info(const char* __n, int __quals, 276 const std::type_info* __type) 277 : std::type_info(__n), __flags(__quals), __pointee(__type) 278 { } 279 280 virtual 281 ~__pbase_type_info(); 282 283 // Implementation defined type. 284 enum __masks 285 { 286 __const_mask = 0x1, 287 __volatile_mask = 0x2, 288 __restrict_mask = 0x4, 289 __incomplete_mask = 0x8, 290 __incomplete_class_mask = 0x10, 291 __transaction_safe_mask = 0x20, 292 __noexcept_mask = 0x40 293 }; 294 295 protected: 296 __pbase_type_info(const __pbase_type_info&); 297 298 __pbase_type_info& 299 operator=(const __pbase_type_info&); 300 301 // Implementation defined member functions. 302 virtual bool 303 __do_catch(const std::type_info* __thr_type, void** __thr_obj, 304 unsigned int __outer) const; 305 306 inline virtual bool 307 __pointer_catch(const __pbase_type_info* __thr_type, void** __thr_obj, 308 unsigned __outer) const; 309 }; 310 311 inline bool __pbase_type_info:: __pointer_catch(const __pbase_type_info * thrown_type,void ** thr_obj,unsigned outer)312 __pointer_catch (const __pbase_type_info *thrown_type, 313 void **thr_obj, 314 unsigned outer) const 315 { 316 return __pointee->__do_catch (thrown_type->__pointee, thr_obj, outer + 2); 317 } 318 319 // Type information for simple pointers. 320 class __pointer_type_info : public __pbase_type_info 321 { 322 public: 323 explicit __pointer_type_info(const char * __n,int __quals,const std::type_info * __type)324 __pointer_type_info(const char* __n, int __quals, 325 const std::type_info* __type) 326 : __pbase_type_info (__n, __quals, __type) { } 327 328 329 virtual 330 ~__pointer_type_info(); 331 332 protected: 333 // Implementation defined member functions. 334 virtual bool 335 __is_pointer_p() const; 336 337 virtual bool 338 __pointer_catch(const __pbase_type_info* __thr_type, void** __thr_obj, 339 unsigned __outer) const; 340 }; 341 342 class __class_type_info; 343 344 // Type information for a pointer to member variable. 345 class __pointer_to_member_type_info : public __pbase_type_info 346 { 347 public: 348 __class_type_info* __context; // Class of the member. 349 350 explicit __pointer_to_member_type_info(const char * __n,int __quals,const std::type_info * __type,__class_type_info * __klass)351 __pointer_to_member_type_info(const char* __n, int __quals, 352 const std::type_info* __type, 353 __class_type_info* __klass) 354 : __pbase_type_info(__n, __quals, __type), __context(__klass) { } 355 356 virtual 357 ~__pointer_to_member_type_info(); 358 359 protected: 360 __pointer_to_member_type_info(const __pointer_to_member_type_info&); 361 362 __pointer_to_member_type_info& 363 operator=(const __pointer_to_member_type_info&); 364 365 // Implementation defined member function. 366 virtual bool 367 __pointer_catch(const __pbase_type_info* __thr_type, void** __thr_obj, 368 unsigned __outer) const; 369 }; 370 371 // Helper class for __vmi_class_type. 372 class __base_class_type_info 373 { 374 public: 375 const __class_type_info* __base_type; // Base class type. 376 #ifdef _GLIBCXX_LLP64 377 long long __offset_flags; // Offset and info. 378 #else 379 long __offset_flags; // Offset and info. 380 #endif 381 382 enum __offset_flags_masks 383 { 384 __virtual_mask = 0x1, 385 __public_mask = 0x2, 386 __hwm_bit = 2, 387 __offset_shift = 8 // Bits to shift offset. 388 }; 389 390 // Implementation defined member functions. 391 bool __is_virtual_p()392 __is_virtual_p() const 393 { return __offset_flags & __virtual_mask; } 394 395 bool __is_public_p()396 __is_public_p() const 397 { return __offset_flags & __public_mask; } 398 399 ptrdiff_t __offset()400 __offset() const 401 { 402 // This shift, being of a signed type, is implementation 403 // defined. GCC implements such shifts as arithmetic, which is 404 // what we want. 405 return static_cast<ptrdiff_t>(__offset_flags) >> __offset_shift; 406 } 407 }; 408 409 // Type information for a class. 410 class __class_type_info : public std::type_info 411 { 412 public: 413 explicit __class_type_info(const char * __n)414 __class_type_info (const char *__n) : type_info(__n) { } 415 416 virtual 417 ~__class_type_info (); 418 419 // Implementation defined types. 420 // The type sub_kind tells us about how a base object is contained 421 // within a derived object. We often do this lazily, hence the 422 // UNKNOWN value. At other times we may use NOT_CONTAINED to mean 423 // not publicly contained. 424 enum __sub_kind 425 { 426 // We have no idea. 427 __unknown = 0, 428 429 // Not contained within us (in some circumstances this might 430 // mean not contained publicly) 431 __not_contained, 432 433 // Contained ambiguously. 434 __contained_ambig, 435 436 // Via a virtual path. 437 __contained_virtual_mask = __base_class_type_info::__virtual_mask, 438 439 // Via a public path. 440 __contained_public_mask = __base_class_type_info::__public_mask, 441 442 // Contained within us. 443 __contained_mask = 1 << __base_class_type_info::__hwm_bit, 444 445 __contained_private = __contained_mask, 446 __contained_public = __contained_mask | __contained_public_mask 447 }; 448 449 struct __upcast_result; 450 struct __dyncast_result; 451 452 protected: 453 // Implementation defined member functions. 454 virtual bool 455 __do_upcast(const __class_type_info* __dst_type, void**__obj_ptr) const; 456 457 virtual bool 458 __do_catch(const type_info* __thr_type, void** __thr_obj, 459 unsigned __outer) const; 460 461 public: 462 // Helper for upcast. See if DST is us, or one of our bases. 463 // Return false if not found, true if found. 464 virtual bool 465 __do_upcast(const __class_type_info* __dst, const void* __obj, 466 __upcast_result& __restrict __result) const; 467 468 // Indicate whether SRC_PTR of type SRC_TYPE is contained publicly 469 // within OBJ_PTR. OBJ_PTR points to a base object of our type, 470 // which is the destination type. SRC2DST indicates how SRC 471 // objects might be contained within this type. If SRC_PTR is one 472 // of our SRC_TYPE bases, indicate the virtuality. Returns 473 // not_contained for non containment or private containment. 474 inline __sub_kind 475 __find_public_src(ptrdiff_t __src2dst, const void* __obj_ptr, 476 const __class_type_info* __src_type, 477 const void* __src_ptr) const; 478 479 // Helper for dynamic cast. ACCESS_PATH gives the access from the 480 // most derived object to this base. DST_TYPE indicates the 481 // desired type we want. OBJ_PTR points to a base of our type 482 // within the complete object. SRC_TYPE indicates the static type 483 // started from and SRC_PTR points to that base within the most 484 // derived object. Fill in RESULT with what we find. Return true 485 // if we have located an ambiguous match. 486 virtual bool 487 __do_dyncast(ptrdiff_t __src2dst, __sub_kind __access_path, 488 const __class_type_info* __dst_type, const void* __obj_ptr, 489 const __class_type_info* __src_type, const void* __src_ptr, 490 __dyncast_result& __result) const; 491 492 // Helper for find_public_subobj. SRC2DST indicates how SRC_TYPE 493 // bases are inherited by the type started from -- which is not 494 // necessarily the current type. The current type will be a base 495 // of the destination type. OBJ_PTR points to the current base. 496 virtual __sub_kind 497 __do_find_public_src(ptrdiff_t __src2dst, const void* __obj_ptr, 498 const __class_type_info* __src_type, 499 const void* __src_ptr) const; 500 }; 501 502 // Type information for a class with a single non-virtual base. 503 class __si_class_type_info : public __class_type_info 504 { 505 public: 506 const __class_type_info* __base_type; 507 508 explicit __si_class_type_info(const char * __n,const __class_type_info * __base)509 __si_class_type_info(const char *__n, const __class_type_info *__base) 510 : __class_type_info(__n), __base_type(__base) { } 511 512 virtual 513 ~__si_class_type_info(); 514 515 protected: 516 __si_class_type_info(const __si_class_type_info&); 517 518 __si_class_type_info& 519 operator=(const __si_class_type_info&); 520 521 // Implementation defined member functions. 522 virtual bool 523 __do_dyncast(ptrdiff_t __src2dst, __sub_kind __access_path, 524 const __class_type_info* __dst_type, const void* __obj_ptr, 525 const __class_type_info* __src_type, const void* __src_ptr, 526 __dyncast_result& __result) const; 527 528 virtual __sub_kind 529 __do_find_public_src(ptrdiff_t __src2dst, const void* __obj_ptr, 530 const __class_type_info* __src_type, 531 const void* __sub_ptr) const; 532 533 virtual bool 534 __do_upcast(const __class_type_info*__dst, const void*__obj, 535 __upcast_result& __restrict __result) const; 536 }; 537 538 // Type information for a class with multiple and/or virtual bases. 539 class __vmi_class_type_info : public __class_type_info 540 { 541 public: 542 unsigned int __flags; // Details about the class hierarchy. 543 unsigned int __base_count; // Number of direct bases. 544 545 // The array of bases uses the trailing array struct hack so this 546 // class is not constructable with a normal constructor. It is 547 // internally generated by the compiler. 548 __base_class_type_info __base_info[1]; // Array of bases. 549 550 explicit __vmi_class_type_info(const char * __n,int ___flags)551 __vmi_class_type_info(const char* __n, int ___flags) 552 : __class_type_info(__n), __flags(___flags), __base_count(0) { } 553 554 virtual 555 ~__vmi_class_type_info(); 556 557 // Implementation defined types. 558 enum __flags_masks 559 { 560 __non_diamond_repeat_mask = 0x1, // Distinct instance of repeated base. 561 __diamond_shaped_mask = 0x2, // Diamond shaped multiple inheritance. 562 __flags_unknown_mask = 0x10 563 }; 564 565 protected: 566 // Implementation defined member functions. 567 virtual bool 568 __do_dyncast(ptrdiff_t __src2dst, __sub_kind __access_path, 569 const __class_type_info* __dst_type, const void* __obj_ptr, 570 const __class_type_info* __src_type, const void* __src_ptr, 571 __dyncast_result& __result) const; 572 573 virtual __sub_kind 574 __do_find_public_src(ptrdiff_t __src2dst, const void* __obj_ptr, 575 const __class_type_info* __src_type, 576 const void* __src_ptr) const; 577 578 virtual bool 579 __do_upcast(const __class_type_info* __dst, const void* __obj, 580 __upcast_result& __restrict __result) const; 581 }; 582 583 // Exception handling forward declarations. 584 struct __cxa_exception; 585 struct __cxa_refcounted_exception; 586 struct __cxa_dependent_exception; 587 struct __cxa_eh_globals; 588 589 extern "C" 590 { 591 // Dynamic cast runtime. 592 593 // src2dst has the following possible values 594 // >-1: src_type is a unique public non-virtual base of dst_type 595 // dst_ptr + src2dst == src_ptr 596 // -1: unspecified relationship 597 // -2: src_type is not a public base of dst_type 598 // -3: src_type is a multiple public non-virtual base of dst_type 599 void* 600 __dynamic_cast(const void* __src_ptr, // Starting object. 601 const __class_type_info* __src_type, // Static type of object. 602 const __class_type_info* __dst_type, // Desired target type. 603 ptrdiff_t __src2dst); // How src and dst are related. 604 605 606 // Exception handling runtime. 607 608 // The __cxa_eh_globals for the current thread can be obtained by using 609 // either of the following functions. The "fast" version assumes at least 610 // one prior call of __cxa_get_globals has been made from the current 611 // thread, so no initialization is necessary. 612 __cxa_eh_globals* 613 __cxa_get_globals() _GLIBCXX_NOTHROW __attribute__ ((__const__)); 614 615 __cxa_eh_globals* 616 __cxa_get_globals_fast() _GLIBCXX_NOTHROW __attribute__ ((__const__)); 617 618 // Free the space allocated for the primary exception. 619 void 620 __cxa_free_exception(void*) _GLIBCXX_NOTHROW; 621 622 // Throw the exception. 623 void 624 __cxa_throw(void*, std::type_info*, void (_GLIBCXX_CDTOR_CALLABI *) (void *)) 625 __attribute__((__noreturn__)); 626 627 // Used to implement exception handlers. 628 void* 629 __cxa_get_exception_ptr(void*) _GLIBCXX_NOTHROW __attribute__ ((__pure__)); 630 631 void* 632 __cxa_begin_catch(void*) _GLIBCXX_NOTHROW; 633 634 void 635 __cxa_end_catch(); 636 637 void 638 __cxa_rethrow() __attribute__((__noreturn__)); 639 640 // Returns the type_info for the currently handled exception [15.3/8], or 641 // null if there is none. 642 std::type_info* 643 __cxa_current_exception_type() _GLIBCXX_NOTHROW __attribute__ ((__pure__)); 644 645 // GNU Extensions. 646 647 // Allocate memory for a dependent exception. 648 __cxa_dependent_exception* 649 __cxa_allocate_dependent_exception() _GLIBCXX_NOTHROW; 650 651 // Free the space allocated for the dependent exception. 652 void 653 __cxa_free_dependent_exception(__cxa_dependent_exception*) _GLIBCXX_NOTHROW; 654 655 } // extern "C" 656 657 // A magic placeholder class that can be caught by reference 658 // to recognize foreign exceptions. 659 class __foreign_exception 660 { 661 virtual ~__foreign_exception() throw(); 662 virtual void __pure_dummy() = 0; // prevent catch by value 663 }; 664 665 } // namespace __cxxabiv1 666 667 /** @namespace abi 668 * @brief The cross-vendor C++ Application Binary Interface. A 669 * namespace alias to __cxxabiv1, but user programs should use the 670 * alias 'abi'. 671 * 672 * A brief overview of an ABI is given in the libstdc++ FAQ, question 673 * 5.8 (you may have a copy of the FAQ locally, or you can view the online 674 * version at http://gcc.gnu.org/onlinedocs/libstdc++/faq.html#5_8 ). 675 * 676 * GCC subscribes to a cross-vendor ABI for C++, sometimes 677 * called the IA64 ABI because it happens to be the native ABI for that 678 * platform. It is summarized at http://www.codesourcery.com/cxx-abi/ 679 * along with the current specification. 680 * 681 * For users of GCC greater than or equal to 3.x, entry points are 682 * available in <cxxabi.h>, which notes, <em>'It is not normally 683 * necessary for user programs to include this header, or use the 684 * entry points directly. However, this header is available should 685 * that be needed.'</em> 686 */ 687 namespace abi = __cxxabiv1; 688 689 namespace __gnu_cxx 690 { 691 /** 692 * @brief Exception thrown by __cxa_guard_acquire. 693 * @ingroup exceptions 694 * 695 * C++ 2011 6.7 [stmt.dcl]/4: If control re-enters the declaration 696 * recursively while the variable is being initialized, the behavior 697 * is undefined. 698 * 699 * Since we already have a library function to handle locking, we might 700 * as well check for this situation and throw an exception. 701 * We use the second byte of the guard variable to remember that we're 702 * in the middle of an initialization. 703 */ 704 class recursive_init_error: public std::exception 705 { 706 public: 707 recursive_init_error() _GLIBCXX_NOTHROW; 708 virtual ~recursive_init_error() _GLIBCXX_NOTHROW; 709 }; 710 } 711 #endif // __cplusplus 712 713 #pragma GCC visibility pop 714 715 #endif // __CXXABI_H 716