std:: exception

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 .

All member functions of std::exception are constexpr .

(since C++26)

Contents 1 Member functions 2 Standard exception requirements 3 Standard exceptions 4 Notes 5 Defect reports

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 system_error ios_base::failure

(since C++11)

filesystem::filesystem_error

(since C++17)

tx_exception

(TM TS)

nonexistent_local_time ambiguous_local_time format_error

(since C++20)

• bad_typeid
• bad_cast

bad_any_cast bad_optional_access

(since C++17)

bad_expected_access

(since C++23)

bad_weak_ptr 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)

Notes

Feature-test macro	Value	Std	Feature
__cpp_lib_constexpr_exceptions	202411L	(C++26)	constexpr for exception types

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