std::exception

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Utilities library

Language support Type support (basic types, RTTI) Library feature-test macros (C++20) Dynamic memory management Program utilities Coroutine support (C++20) Variadic functions is_constant_evaluated (C++20) is_within_lifetime (C++26) initializer_list (C++11) source_location (C++20) Three-way comparison three_way_comparablethree_way_comparable_with (C++20)(C++20) strong_ordering (C++20) weak_ordering (C++20) partial_ordering (C++20) common_comparison_category (C++20) compare_three_way_result (C++20) compare_three_way (C++20) strong_order (C++20) weak_order (C++20) partial_order (C++20) compare_strong_order_fallback (C++20) compare_weak_order_fallback (C++20) compare_partial_order_fallback (C++20)   is_eqis_ltis_lteq (C++20)(C++20)(C++20)   is_neqis_gtis_gteq (C++20)(C++20)(C++20)

General utilities Date and time Function objects Formatting library (C++20)   bitset hash (C++11) Relational operators (deprecated in C++20) rel_ops::operator!=rel_ops::operator>    rel_ops::operator<=rel_ops::operator>= Integer comparison functions cmp_equalcmp_lesscmp_less_than (C++20)(C++20)(C++20)   cmp_not_equalcmp_greatercmp_greater_than (C++20)(C++20)(C++20) in_range (C++20) Swap and type operations swap ranges::swap (C++20) exchange (C++14) declval (C++11) to_underlying (C++23) forward (C++11) forward_like (C++23) move (C++11) move_if_noexcept (C++11) as_const (C++17) Common vocabulary types pair tuple (C++11) optional (C++17) any (C++17) variant (C++17) tuple_size (C++11) tuple_element (C++11) apply (C++17) make_from_tuple (C++17) expected (C++23) Elementary string conversions to_chars (C++17) from_chars (C++17) chars_format (C++17) to_chars_result (C++17) from_chars_result (C++17)

 

Diagnostics library

Exception handling exception uncaught_exceptionuncaught_exceptions (until C++20*)  (C++17) exception_ptr (C++11) make_exception_ptr (C++11) current_exception (C++11) rethrow_exception (C++11) nested_exception (C++11) throw_with_nested (C++11) rethrow_if_nested (C++11) Exception handling failures terminate terminate_handler get_terminate (C++11) set_terminate bad_exception unexpected (until C++17*) unexpected_handler (until C++17*) get_unexpected (until C++17*) set_unexpected (until C++17*) Error numbers Error codes errno Assertions assert

Exception categories logic_error invalid_argument domain_error length_error out_of_range runtime_error range_error overflow_error underflow_error tx_exception (TM TS) System error error_category (C++11) generic_category (C++11) system_category (C++11) error_condition (C++11) errc (C++11) error_code (C++11) system_error (C++11) Stacktrace stacktrace_entry (C++23) basic_stacktrace (C++23) Debugging support is_debugger_present (C++26) breakpoint_if_debugging (C++26) breakpoint (C++26)

 

std::exception

Member functions

exception::exception

exception::~exception

exception::operator=

exception::what

 

Defined in header <exception>
class exception;

Provides consistent interface to handle errors through the throw expression.

All exceptions generated by the standard library inherit from std::exception.

Member functions

(constructor)	constructs the exception object (public member function)
(destructor) [virtual]	destroys the exception object (virtual public member function)
operator=	copies exception object (public member function)
what [virtual]	returns an explanatory string (virtual public member function)

Standard exception requirements

Each standard library class T that derives from std::exception has the following publicly accessible member functions, each of them do not exit with an exception(until C++11)having a non-throwing exception specification(since C++11):

• default constructor (unless other constructors are provided)
• copy constructor
• copy assignment operator

The copy constructor and the copy assignment operator meet the following postcondition:

• If two objects lhs and rhs both have dynamic type T and lhs is a copy of rhs, then std::strcmp(lhs.what(), rhs.what()) is equal to ​0​.

The what() member function of each such T satisfies the constraints specified for std::exception::what().

Standard exceptions

• logic_error

• invalid_argument
• domain_error
• length_error
• out_of_range
• future_error (since C++11)

• runtime_error

• range_error
• overflow_error
• underflow_error
• regex_error (since C++11)
• system_error (since C++11)

• ios_base::failure (since C++11)
• filesystem::filesystem_error (since C++17)

• tx_exception (TM TS)
• nonexistent_local_time (since C++20)
• ambiguous_local_time (since C++20)
• format_error (since C++20)

• bad_typeid
• bad_cast

• bad_any_cast (since C++17)

• bad_optional_access (since C++17)
• bad_expected_access (since C++23)
• bad_weak_ptr (since C++11)
• bad_function_call (since C++11)
• bad_alloc

• bad_array_new_length (since C++11)

• bad_exception
• ios_base::failure (until C++11)
• bad_variant_access (since C++17)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 471	C++98	there was no requirement on standard library classes derived from std::exception	added