Note
Access to this page requires authorization. You can try signing in or changing directories.
Access to this page requires authorization. You can try changing directories.
The latest version of this topic can be found at error_code Class.
Represents low-level system errors that are implementation-specific.
Syntax
class error_code;
Remarks
An object of type error_code class stores an error code value and a pointer to an object that represents a category of error codes that describe reported low-level system errors.
Constructors
| error_code | Constructs an object of type error_code. |
Typedefs
| value_type | A type that represents the stored error code value. |
Member Functions
| assign | Assigns an error code value and category to an error code. |
| category | Returns the error category. |
| clear | Clears the error code value and category. |
| default_error_condition | Returns the default error condition. |
| message | Returns the name of the error code. |
Operators
| operator== | Tests for equality between error_code objects. |
| operator!= | Tests for inequality between error_code objects. |
| operator< | Tests if the error_code object is less than the error_code object passed in for comparison. |
| operator= | Assigns a new enumeration value to the error_code object. |
| operator bool | Casts a variable of type error_code. |
Requirements
Header: <system_error>
Namespace: std
error_code::assign
Assigns an error code value and category to an error code.
void assign(value_type val, const error_category& _Cat);
Parameters
| Parameter | Description |
|---|---|
val |
The error code value to store in the error_code. |
_Cat |
The error category to store in the error_code. |
Remarks
The member function stores val as the error code value and a pointer to _Cat.
error_code::category
Returns the error category.
const error_category& category() const;
Remarks
error_code::clear
Clears the error code value and category.
clear();
Remarks
The member function stores a zero error code value and a pointer to the generic_category object.
error_code::default_error_condition
Returns the default error condition.
error_condition default_error_condition() const;
Return Value
The error_condition specified by default_error_condition.
Remarks
This member function returns category().default_error_condition(value()).
error_code::error_code
Constructs an object of type error_code.
error_code();
error_code(value_type val, const error_category& _Cat);
template <class _Enum>
error_code(_Enum _Errcode,
typename enable_if<is_error_code_enum<_Enum>::value,
error_code>::type* = 0);
Parameters
| Parameter | Description |
|---|---|
val |
The error code value to store in the error_code. |
_Cat |
The error category to store in the error_code. |
_Errcode |
The enumeration value to store in the error_code. |
Remarks
The first constructor stores a zero error code value and a pointer to the generic_category.
The second constructor stores val as the error code value and a pointer to error_category.
The third constructor stores (value_type)_Errcode as the error code value and a pointer to the generic_category.
error_code::message
Returns the name of the error code.
string message() const;
Return Value
A string representing the name of the error code.
Remarks
This member function returns category().message(value()).
error_code::operator==
Tests for equality between error_code objects.
bool operator==(const error_code& right) const;
Parameters
| Parameter | Description |
|---|---|
right |
The object to be tested for equality. |
Return Value
true if the objects are equal; false if objects are not equal.
Remarks
The member operator returns category() == right.category() && value == right.value().
error_code::operator!=
Tests for inequality between error_code objects.
bool operator!=(const error_code& right) const;
Parameters
| Parameter | Description |
|---|---|
right |
The object to be tested for inequality. |
Return Value
true if the error_code object is not equal to the error_code object passed in right; otherwise false.
Remarks
The member operator returns !(*this == right).
error_code::operator<
Tests if the error_code object is less than the error_code object passed in for comparison.
bool operator<(const error_code& right) const;
Parameters
| Parameter | Description |
|---|---|
right |
The error_code object to be compared. |
Return Value
true if the error_code object is less than the error_code object passed in for comparison; Otherwise, false.
Remarks
The member operator returns category() < right.category() || category() == right.category() && value < right.value().
error_code::operator=
Assigns a new enumeration value to the error_code object.
template <class _Enum>
typename enable_if<is_error_code_enum<_Enum>::value,
error_code>::type&
operator=(_Enum _Errcode);
Parameters
| Parameter | Description |
|---|---|
_Errcode |
The enumeration value to assign to the error_code object. |
Return Value
A reference to the error_code object that is being assigned the new enumeration value by the member function.
Remarks
The member operator stores (value_type)_Errcode as the error code value and a pointer to the generic_category. It returns *this.
error_code::operator bool
Casts a variable of type error_code.
explicit operator bool() const;
Return Value
The Boolean value of the error_code object.
Remarks
The operator returns a value convertible to true only if value is not equal to zero. The return type is convertible only to bool, not to void * or other known scalar types.
error_code::value
Returns the stored error code value.
value_type value() const;
Return Value
The stored error code value of type value_type.
Remarks
error_code::value_type
A type that represents the stored error code value.
typedef int value_type;
Remarks
This type definition is a synonym for int.