nullable type

Outside of functional programming, these are known as nullable types.

This need can be achieved with a nullable type.

For exception handling, one can return a nullable type, or raise an exception.

Nullable types offer an intermediate approach; see below.

Nullable type implementations usually adhere to the null object pattern.

This in contrast of nullable types which allows value types to be set as null.

The following programming languages support nullable types.

Additions included partial classes, anonymous methods, nullable types, and generics (somewhat similar to C++ templates).

NET 2.0, stored procedures, generics, and nullable types.

Nullable types such as strings have the difficulty of historically different definitions for NULL.

The primary use of this operator is to assign a nullable type to a non-nullable type with an easy syntax:

There is a more general and formal concept that extend the nullable type concept, it comes from option types, which enforce explicit handling of the exceptional case.

Nullable (lifted) types to allow for a better match with query providers that support nullable types, like e.g. SQL.

Null (called "Nothing" in Visual Basic), a value that a variable of nullable type in a computer program can take to indicate the absence of an instance of its data type.

For returning a value of one of several types, a tagged union can be used instead; the most common cases are nullable types (option types), where the return value can be null to indicate failure.

Primitive types such as integers and booleans cannot generally be null, but the corresponding nullable types (nullable integer and nullable boolean, respectively) can also assume the NULL value.

In statically-typed languages, a nullable type is an option type (in functional programming terms), while in dynamically-typed languages (where values have types, but variables do not), equivalent behavior is provided by having a single null value.

In programming, nullable types are a feature of the type system of some programming languages which allow the value to be set to the special value NULL instead of the usual possible values of the data type.

Null pointers are routinely used to represent conditions such as the end of a list of unknown length or the failure to perform some action; this use of null pointers can be compared to nullable types and to the Nothing value in an option type.

Nullable types received an improvement at the end of August 2005, shortly before the official launch, to improve their boxing characteristics: a nullable variable which is assigned null is not actually a null reference, but rather an instance of with property equal to .