error_condition Class

 

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Represents user-defined error codes.

class error_condition;

An object of type error_condition stores an error code value and a pointer to an object that represents a category of error codes used for reported user-defined errors.

Constructors

error_conditionConstructs an object of type error_condition.

Typedefs

value_typeA type that represents the stored error code value.

Member Functions

assignAssigns an error code value and category to an error condition.
categoryReturns the error category.
clearClears the error code value and category.
messageReturns the name of the error code.

Operators

operator==Tests for equality between error_condition objects.
operator!=Tests for inequality between error_condition objects.
operator<Tests if the error_condition object is less than the error_code object passed in for comparison.
operator=Assigns a new enumeration value to the error_condition object.
operator boolCasts a variable of type error_condition.

Header: <system_error>

Namespace: std

Assigns an error code value and category to an error condition.

void assign(value_type val, const error_category& _Cat);

Parameters

ParameterDescription
valThe error code value to store in the error_code.
_CatThe error category to store in the error_code.

Remarks

The member function stores val as the error code value and a pointer to _Cat.

Returns the error category.

const error_category& category() const;

Return Value

A reference to the stored error category

Remarks

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.

Constructs an object of type error_condition.

error_condition();

error_condition(value_type val, const error_category& _Cat);

template <class _Enum>
error_condition(_Enum _Errcode,
    typename enable_if<is_error_condition_enum<_Enum>::value,
    error_code>::type* = 0);

Parameters

ParameterDescription
valThe error code value to store in the error_condition.
_CatThe error category to store in the error_condition.
_ErrcodeThe enumeration value to store in the error_condition.

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.

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()).

Tests for equality between error_condition objects.

bool operator==(const error_condition& right) const;

Parameters

ParameterDescription
rightThe ojbect 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().

Tests for inequality between error_condition objects.

bool operator!=(const error_condition& right) const;

Parameters

ParameterDescription
rightThe object to be tested for inequality.

Return Value

true if the error_condition object is not equal to the error_condition object passed in right; otherwise false.

Remarks

The member operator returns !(*this == right).

Tests if the error_condition object is less than the error_code object passed in for comparison.

bool operator<(const error_condition& right) const;

Parameters

ParameterDescription
rightThe error_condition object to be compared.

Return Value

true if the error_condition object is less than the error_condition object passed in for comparison; Otherwise, false.

Remarks

The member operator returns category() < right.category() || category() == right.category() && value < right.value().

Assigns a new enumeration value to the error_condition object.

template <class _Enum>
error_condition(_Enum error,
    typename enable_if<is_error_condition_enum<_Enum>::value,
    error_condition>::type&
 operator=(Enum _Errcode);

Parameters

ParameterDescription
_ErrcodeThe enumeration value to assign to the error_condition object.

Return Value

A reference to the error_condition object that is being assigned the new enumeration value by the member function.

Remarks

The member operator stores (value_type)error as the error code value and a pointer to the generic_category. It returns *this.

Casts a variable of type error_condition.

explicit operator bool() const;

Return Value

The Boolean value of the error_condition 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.

Returns the stored error code value.

value_type value() const;

Return Value

The stored error code value of type value_type.

Remarks

A type that represents the stored error code value.

typedef int value_type;

Remarks

The type definition is a synonym for int.

error_category Class
<system_error>

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