This header is part of the error handling library.
Includes |
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(C++20) | Three-way comparison operator support |
Classes |
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(C++11) | base class for error categories (class) |
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(C++11) | holds a portable error code (class) |
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(C++11) | the std::error_condition enumeration listing all standard <cerrno> macro constants (class) |
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(C++11) | holds a platform-dependent error code (class) |
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(C++11) | exception class used to report conditions that have an error_code (class) |
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(C++11) | identifies a class as an error_code enumeration (class template) |
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(C++11) | identifies an enumeration as an std::error_condition (class template) |
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(C++11) | hash support for std::error_code (class template specialization) |
Forward declarations |
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Defined in header <functional> |
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(C++11) | hash function object (class template) |
Functions |
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(C++11) | identifies the generic error category (function) |
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(C++11) | identifies the operating system error category (function) |
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(removed in C++20)(removed in C++20)(C++20) | compares two error_codes (function) |
| outputs the value and the category name to an output stream (function) |
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(C++11) | constructs an std::errc error code (function) |
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(removed in C++20)(removed in C++20)(C++20) | compares error_conditions and error_codes (function) |
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(C++11) | constructs an std::errc error condition (function) |
#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, // EAFNOSUPPORT
address_in_use, // EADDRINUSE
address_not_available, // EADDRNOTAVAIL
already_connected, // EISCONN
argument_list_too_long, // E2BIG
argument_out_of_domain, // EDOM
bad_address, // EFAULT
bad_file_descriptor, // EBADF
bad_message, // EBADMSG
broken_pipe, // EPIPE
connection_aborted, // ECONNABORTED
connection_already_in_progress, // EALREADY
connection_refused, // ECONNREFUSED
connection_reset, // ECONNRESET
cross_device_link, // EXDEV
destination_address_required, // EDESTADDRREQ
device_or_resource_busy, // EBUSY
directory_not_empty, // ENOTEMPTY
executable_format_error, // ENOEXEC
file_exists, // EEXIST
file_too_large, // EFBIG
filename_too_long, // ENAMETOOLONG
function_not_supported, // ENOSYS
host_unreachable, // EHOSTUNREACH
identifier_removed, // EIDRM
illegal_byte_sequence, // EILSEQ
inappropriate_io_control_operation, // ENOTTY
interrupted, // EINTR
invalid_argument, // EINVAL
invalid_seek, // ESPIPE
io_error, // EIO
is_a_directory, // EISDIR
message_size, // EMSGSIZE
network_down, // ENETDOWN
network_reset, // ENETRESET
network_unreachable, // ENETUNREACH
no_buffer_space, // ENOBUFS
no_child_process, // ECHILD
no_link, // ENOLINK
no_lock_available, // ENOLCK
no_message_available, // ENODATA
no_message, // ENOMSG
no_protocol_option, // ENOPROTOOPT
no_space_on_device, // ENOSPC
no_stream_resources, // ENOSR
no_such_device_or_address, // ENXIO
no_such_device, // ENODEV
no_such_file_or_directory, // ENOENT
no_such_process, // ESRCH
not_a_directory, // ENOTDIR
not_a_socket, // ENOTSOCK
not_a_stream, // ENOSTR
not_connected, // ENOTCONN
not_enough_memory, // ENOMEM
not_supported, // ENOTSUP
operation_canceled, // ECANCELED
operation_in_progress, // EINPROGRESS
operation_not_permitted, // EPERM
operation_not_supported, // EOPNOTSUPP
operation_would_block, // EWOULDBLOCK
owner_dead, // EOWNERDEAD
permission_denied, // EACCES
protocol_error, // EPROTO
protocol_not_supported, // EPROTONOSUPPORT
read_only_file_system, // EROFS
resource_deadlock_would_occur, // EDEADLK
resource_unavailable_try_again, // EAGAIN
result_out_of_range, // ERANGE
state_not_recoverable, // ENOTRECOVERABLE
stream_timeout, // ETIME
text_file_busy, // ETXTBSY
timed_out, // ETIMEDOUT
too_many_files_open_in_system, // ENFILE
too_many_files_open, // EMFILE
too_many_links, // EMLINK
too_many_symbolic_link_levels, // ELOOP
value_too_large, // EOVERFLOW
wrong_protocol_type, // EPROTOTYPE
};
template<> struct is_error_condition_enum<errc> : true_type {};
// non-member functions
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);
// non-member functions
error_condition make_error_condition(errc e) noexcept;
// comparison functions
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;
// hash support
template<class T> struct hash;
template<> struct hash<error_code>;
template<> struct hash<error_condition>;
// system error support
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;
}std::error_category
namespace std {
class error_category {
public:
constexpr error_category() noexcept;
virtual ~error_category();
error_category(const error_category&) = delete;
error_category& operator=(const error_category&) = delete;
virtual const char* name() const noexcept = 0;
virtual error_condition default_error_condition(int ev) const noexcept;
virtual bool equivalent(int code, const error_condition& condition) const noexcept;
virtual bool equivalent(const error_code& code, int condition) const noexcept;
virtual string message(int ev) const = 0;
bool operator==(const error_category& rhs) const noexcept;
strong_ordering operator<=>(const error_category& rhs) const noexcept;
};
const error_category& generic_category() noexcept;
const error_category& system_category() noexcept;
}std::error_code
namespace std {
class error_code {
public:
// constructors
error_code() noexcept;
error_code(int val, const error_category& cat) noexcept;
template<class ErrorCodeEnum>
error_code(ErrorCodeEnum e) noexcept;
// modifiers
void assign(int val, const error_category& cat) noexcept;
template<class ErrorCodeEnum>
error_code& operator=(ErrorCodeEnum e) noexcept;
void clear() noexcept;
// observers
int value() const noexcept;
const error_category& category() const noexcept;
error_condition default_error_condition() const noexcept;
string message() const;
explicit operator bool() const noexcept;
private:
int val_; // exposition only
const error_category* cat_; // exposition only
};
// non-member functions
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);
}std::error_condition
namespace std {
class error_condition {
public:
// constructors
error_condition() noexcept;
error_condition(int val, const error_category& cat) noexcept;
template<class ErrorConditionEnum>
error_condition(ErrorConditionEnum e) noexcept;
// modifiers
void assign(int val, const error_category& cat) noexcept;
template<class ErrorConditionEnum>
error_condition& operator=(ErrorConditionEnum e) noexcept;
void clear() noexcept;
// observers
int value() const noexcept;
const error_category& category() const noexcept;
string message() const;
explicit operator bool() const noexcept;
private:
int val_; // exposition only
const error_category* cat_; // exposition only
};
}std::system_error
namespace std {
class system_error : public runtime_error {
public:
system_error(error_code ec, const string& what_arg);
system_error(error_code ec, const char* what_arg);
system_error(error_code ec);
system_error(int ev, const error_category& ecat, const string& what_arg);
system_error(int ev, const error_category& ecat, const char* what_arg);
system_error(int ev, const error_category& ecat);
const error_code& code() const noexcept;
const char* what() const noexcept override;
};
}
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