The Third Manifesto proposes to maintain the relational model for databases and to support objects as user-defined types.

In order to construct constant expression data values from user-defined types, constructors can also be declared with .

C++ is designed so that user-defined types should be able to function exactly like native types such as char and int.

On the Java platform, all composite and user-defined types are reference types.

Although the Go programming language is not generally considered an object-oriented language, it does allow methods to be defined on user-defined types.

Both type categories are extensible with user-defined types.

For user-defined types, this implies that the less-than operator must be overloaded.

There is a new type system that enables user-defined types to be used in the Csound language.

LB5 may support arrays of user-defined types.

If it is a user-defined type, the variable is the pointer address, which cannot be modified either.