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Template Parameters

T	Type of the contained value.

Member Typedef Documentation

◆  ValueType

◆  ResultFunctions

构造函数 & 析构函数文档编制

◆  Opt() [1/10]

Default constructor. Creates an Opt with no value.

◆  Opt() [2/10]

Explicit construction with no value. Has the same effect as the default constructor.

◆  Opt() [3/10]

Converting copy constructor. For semantics, see non-converting variant. This constructor is enabled only if T is constructible from const U&.

◆  Opt() [4/10]

Converting move constructor. For semantics, see non-converting variant. This constructor is enabled only if T is constructible from U&&.

◆  Opt() [5/10]

Copy-from-value constructor. Constructs object as if direct-initializing the contained value with the passed value, i.e. T thisValue(value).

◆  Opt() [6/10]

Move-from-value constructor. Constructs object as if direct-initializing the contained value with the passed value, i.e. T thisValue(std::move(value)).

◆  Opt() [7/10]

Constructs from optional const-reference. (1) If src references no value, this object will not contain a value either. (2) If src references a value, the value of this object is copy-constructed with the former, i.e. T thisValue(*src). This constructor is enabled only if T is constructible from const U&.

◆  Opt() [8/10]

Constructs from optional reference. For semantics, see const-reference variant. This constructor is enabled only if T is constructible from U&.

◆  Opt() [9/10]

Constructs from optional rvalue-reference. For semantics, see const-reference variant, with the following differences: (2) If src references a value, the value of this object is copy-constructed with the former, i.e. T thisValue(*src). This constructor is enabled only if T is constructible from U&&.

◆  Opt() [10/10]

Emplace constructor. Constructs the contained value in-place with given arguments, i.e. T thisValue(std::forward<ARGS>(args) ...).

◆  ~Opt()

If this Opt contains a value, the latter is destroyed.

成员函数文档编制

◆  operator=() [1/6]

Assignment with no value. If this object contains a value, the destructor of the contained value is called. Afterwards, this object no longer contains a value.

◆  MAXON_DECLARE_CONDITIONAL_COPY_CONSTRUCTOR()

Copy constructor. (1) If src contains no value, this object will not contain a value either. (2) If src contains a value, the value of this object is copy-constructed with the former, i.e. T thisValue(srcValue). This constructor is enabled only if T is copy constructible.

◆  operator=() [2/6]

Converting copy assignment. For semantics, see non-converting variant. This operator is enabled only if T is assignable from const U&.

◆  MAXON_DECLARE_CONDITIONAL_MOVE_CONSTRUCTOR()

Move constructor. (1) If src contains no value, this object will not contain a value either. (2) If src contains a value, the value of this object is move-constructed with the former, i.e. T thisValue(std::move(srcValue)). Note that afterwards, src will still have a value, which has been moved from. This constructor is enabled only if T is move constructible.

◆  operator=() [3/6]

Converting move assignment. For semantics, see non-converting variant. (1,2) See copy assignment. (3) If only src contains a value, behavior is identical to move constructor. (4) If both this object and src contain a value, the contained value is assigned src's value, i.e. thisValue = std::move(srcValue). This operator is enabled only if T is assignable from U&&.

◆  operator=() [4/6]

Assign from optional const-reference. (1) If this object contains no value and src references no value, this function does nothing. (2) If this object contains a value and src references no value, behavior is identical to assignment with no value. (3) If this object contains no value and src references a value, behavior is identical to copy-from-value constructor. (4) If this object contains a value and src references a value, the value of this object is assigned from *src. This operator is enabled only if T is assignable from const U&.

◆  operator=() [5/6]

Assign from optional reference. For semantics, see const-reference variant. This operator is enabled only if T is assignable from U&.

◆  operator=() [6/6]

Assign from optional rvalue-reference. For semantics, see const-reference variant, with the following differences: (3) If this object contains no value and src references a value, behavior is identical to move-from-value constructor. (4) If this object contains a value and src references a value, the value of this object is assigned from std::move(*src). This operator is enabled only if T is assignable from U&&.

◆  Emplace()

Constructs a new value in-place. Behavior is similar to the in-place constructor, with the difference that if the object already contained a value, the current value is destructed first.

◆  CopyFrom()

Semantically equivalent to copy assignment, but uses CopyFrom() of the contained value. Use this if copying T may result in an error. This function is enabled only if T implements CopyFrom() .

◆  Reset()

◆  HasValue()

Returns true if this Opt contains a value.

◆  operator Bool()

◆  GetValue() [1/2]

Returns the contained value, or IllegalState error if Opt contained no value.

◆  GetValue() [2/2]

◆  GetValueOr()

Returns the contained value, or a default value if Opt contained no value.

◆  GetValueOrNull()

Returns the contained value, or a null value if Opt contained no value.

◆  MoveValue()

Returns the moved contained value, or IllegalState error if object contained no value.

◆  MoveValueOr()

Returns the moved contained value, or a default value if object contained no value.

◆  MoveValueOrNull()

Returns the moved contained value, or a null value if Opt contained no value.

◆  operator->() [1/2]

Returns a pointer to the contained value. Results in undefined behavior if object contained no value.

◆  operator->() [2/2]

◆  operator*() [1/2]

Returns a reference to the contained value. Results in undefined behavior if object contained no value.

◆  operator*() [2/2]

◆  ToString()

Returns a formated string representation of this optional value.

◆  GetHashCode()

◆  CheckValue()

◆  GetValueRef() [1/2]

◆  GetValueRef() [2/2]

Friends And Related Function Documentation

◆  Opt

Member Data Documentation

◆  this

Copy assignment. (1) If both this object and src contain no value, this function does nothing. (2) If only this object contains a value, behavior is identical to assignment with no value. (3) If only src contains a value, behavior is identical to copy constructor. (4) If both this object and src contain a value, the contained value is assigned src's value, i.e. thisValue = srcValue. This operator is enabled only if T is copy assignable.

Move assignment. (1,2) See copy assignment. (3) If only src contains a value, behavior is identical to move constructor. (4) If both this object and src contain a value, the contained value is assigned src's value, i.e. thisValue = std::move(srcValue). This operator is enabled only if T is move assignable.

◆  _storage

• maxon
• Opt