1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___EXCEPTION_EXCEPTION_H 10 #define _LIBCPP___EXCEPTION_EXCEPTION_H 11 12 #include <__config> 13 14 // <vcruntime_exception.h> defines its own std::exception and std::bad_exception types, 15 // which we use in order to be ABI-compatible with other STLs on Windows. 16 #if defined(_LIBCPP_ABI_VCRUNTIME) 17 # include <vcruntime_exception.h> 18 #endif 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 # pragma GCC system_header 22 #endif 23 24 namespace std { // purposefully not using versioning namespace 25 26 #if defined(_LIBCPP_ABI_VCRUNTIME) && (!defined(_HAS_EXCEPTIONS) || _HAS_EXCEPTIONS != 0) 27 // The std::exception class was already included above, but we're explicit about this condition here for clarity. 28 29 #elif defined(_LIBCPP_ABI_VCRUNTIME) && _HAS_EXCEPTIONS == 0 30 // However, <vcruntime_exception.h> does not define std::exception and std::bad_exception 31 // when _HAS_EXCEPTIONS == 0. 32 // 33 // Since libc++ still wants to provide the std::exception hierarchy even when _HAS_EXCEPTIONS == 0 34 // (after all those are simply types like any other), we define an ABI-compatible version 35 // of the VCRuntime std::exception and std::bad_exception types in that mode. 36 37 struct __std_exception_data { 38 char const* _What; 39 bool _DoFree; 40 }; 41 42 class exception { // base of all library exceptions 43 public: 44 exception() _NOEXCEPT : __data_() {} 45 46 explicit exception(char const* __message) _NOEXCEPT : __data_() { 47 __data_._What = __message; 48 __data_._DoFree = true; 49 } 50 51 exception(exception const&) _NOEXCEPT {} 52 53 exception& operator=(exception const&) _NOEXCEPT { return *this; } 54 55 virtual ~exception() _NOEXCEPT {} 56 57 virtual char const* what() const _NOEXCEPT { return __data_._What ? __data_._What : "Unknown exception"; } 58 59 private: 60 __std_exception_data __data_; 61 }; 62 63 class bad_exception : public exception { 64 public: 65 bad_exception() _NOEXCEPT : exception("bad exception") {} 66 }; 67 68 #else // !defined(_LIBCPP_ABI_VCRUNTIME) 69 // On all other platforms, we define our own std::exception and std::bad_exception types 70 // regardless of whether exceptions are turned on as a language feature. 71 72 class _LIBCPP_EXPORTED_FROM_ABI exception { 73 public: 74 _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {} 75 _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT = default; 76 _LIBCPP_HIDE_FROM_ABI exception& operator=(const exception&) _NOEXCEPT = default; 77 78 virtual ~exception() _NOEXCEPT; 79 virtual const char* what() const _NOEXCEPT; 80 }; 81 82 class _LIBCPP_EXPORTED_FROM_ABI bad_exception : public exception { 83 public: 84 _LIBCPP_HIDE_FROM_ABI bad_exception() _NOEXCEPT {} 85 _LIBCPP_HIDE_FROM_ABI bad_exception(const bad_exception&) _NOEXCEPT = default; 86 _LIBCPP_HIDE_FROM_ABI bad_exception& operator=(const bad_exception&) _NOEXCEPT = default; 87 ~bad_exception() _NOEXCEPT override; 88 const char* what() const _NOEXCEPT override; 89 }; 90 #endif // !_LIBCPP_ABI_VCRUNTIME 91 92 } // namespace std 93 94 #endif // _LIBCPP___EXCEPTION_EXCEPTION_H 95