#include <compare>
namespace std {
class error_category;
const error_category& generic_category() noexcept;
const error_category& system_category() noexcept;
class error_code;
class error_condition;
class system_error;
template<class T>
struct is_error_code_enum : public false_type {};
template<class T>
struct is_error_condition_enum : public false_type {};
enum class errc {
address_family_not_supported,
address_in_use,
address_not_available,
already_connected,
argument_list_too_long,
argument_out_of_domain,
bad_address,
bad_file_descriptor,
bad_message,
broken_pipe,
connection_aborted,
connection_already_in_progress,
connection_refused,
connection_reset,
cross_device_link,
destination_address_required,
device_or_resource_busy,
directory_not_empty,
executable_format_error,
file_exists,
file_too_large,
filename_too_long,
function_not_supported,
host_unreachable,
identifier_removed,
illegal_byte_sequence,
inappropriate_io_control_operation,
interrupted,
invalid_argument,
invalid_seek,
io_error,
is_a_directory,
message_size,
network_down,
network_reset,
network_unreachable,
no_buffer_space,
no_child_process,
no_link,
no_lock_available,
no_message_available,
no_message,
no_protocol_option,
no_space_on_device,
no_stream_resources,
no_such_device_or_address,
no_such_device,
no_such_file_or_directory,
no_such_process,
not_a_directory,
not_a_socket,
not_a_stream,
not_connected,
not_enough_memory,
not_supported,
operation_canceled,
operation_in_progress,
operation_not_permitted,
operation_not_supported,
operation_would_block,
owner_dead,
permission_denied,
protocol_error,
protocol_not_supported,
read_only_file_system,
resource_deadlock_would_occur,
resource_unavailable_try_again,
result_out_of_range,
state_not_recoverable,
stream_timeout,
text_file_busy,
timed_out,
too_many_files_open_in_system,
too_many_files_open,
too_many_links,
too_many_symbolic_link_levels,
value_too_large,
wrong_protocol_type,
};
template<> struct is_error_condition_enum<errc> : true_type {};
error_code make_error_code(errc e) noexcept;
template<class charT, class traits>
basic_ostream<charT, traits>&
operator<<(basic_ostream<charT, traits>& os, const error_code& ec);
error_condition make_error_condition(errc e) noexcept;
bool operator==(const error_code& lhs, const error_code& rhs) noexcept;
bool operator==(const error_code& lhs, const error_condition& rhs) noexcept;
bool operator==(const error_condition& lhs, const error_condition& rhs) noexcept;
strong_ordering operator<=>(const error_code& lhs, const error_code& rhs) noexcept;
strong_ordering operator<=>(const error_condition& lhs, const error_condition& rhs) noexcept;
template<class T> struct hash;
template<> struct hash<error_code>;
template<> struct hash<error_condition>;
template<class T>
inline constexpr bool is_error_code_enum_v = is_error_code_enum<T>::value;
template<class T>
inline constexpr bool is_error_condition_enum_v = is_error_condition_enum<T>::value;
}
The value of each
enum errc constant shall be the same as
the value of the
<cerrno> macro shown in the above synopsis
.Whether or not the
<system_error> implementation
exposes the
<cerrno> macros is unspecified
.The
is_error_code_enum and
is_error_condition_enum may be
specialized for program-defined types to indicate that such types are eligible
for
class error_code and
class error_condition automatic
conversions, respectively
.