std::operator==,!=,<,<=>(std::error_code)

 

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::error_code

Member functions

error_code::error_code

error_code::operator=

error_code::assign

Modifiers

error_code::clear

Observers

error_code::value

error_code::category

error_code::default_error_condition

error_code::message

error_code::operator bool

Non-member functions

operator==operator!=operator<operator<=> (until C++20)(until C++20)(C++20)

operator<<

Helper classes

is_error_code_enum

hash<std::error_code>

 

Defined in header <system_error>
bool operator==( const std::error_code& lhs,                  const std::error_code& rhs ) noexcept;	(1)	(since C++11)
bool operator!=( const std::error_code& lhs,                  const std::error_code& rhs ) noexcept;	(2)	(since C++11) (until C++20)
bool operator<( const std::error_code& lhs,                 const std::error_code& rhs ) noexcept;	(3)	(since C++11) (until C++20)
std::strong_ordering operator<=>( const std::error_code& lhs,                                   const std::error_code& rhs ) noexcept;	(4)	(since C++20)

Compares two error code objects.

1) Compares lhs and rhs for equality.

2) Compares lhs and rhs for equality.

3) Checks whether lhs is less than rhs.

4) Obtains three-way comparison result of lhs and rhs.

The <, <=, >, >=, and != operators are synthesized from operator<=> and operator== respectively.

(since C++20)

Parameters

lhs, rhs

-

error codes to compare

Return value

1) true if the error category and error value compare equal.

2) true if the error category or error value compare are not equal.

3) true if lhs.category() < rhs.category(). Otherwise, true if lhs.category() == rhs.category() && lhs.value() < rhs.value(). Otherwise, false.

4) lhs.category() <=> rhs.category() if it is not std::strong_ordering::equal. Otherwise, lhs.value() <=> rhs.value().

See also

category	obtains the error_category for this error_code (public member function)
value	obtains the value of the error_code (public member function)
operator==operator!=operator<operator<=> (removed in C++20)(removed in C++20)(C++20)	compares error_conditions and error_codes (function)