In computer science, an instance is an occurrence of a software element that is based on a type definition.
[1]: 1.3.2
When created, an occurrence is said to have been instantiated, and both the creation process and the result of creation are called instantiation.
- Class instance
- An object-oriented programming (OOP) object created from a class. Each instance of a class shares a data layout but has its own memory allocation.
- Procedural instance
- Although isn't common the use of this concept in computer science each procedure call also was considered an "instance" of the procedure in Simula. [1]: 1.3.2
- Computer instance
- An occurrence of a virtual machine which typically includes storage, a virtual CPU.
- Polygonal model
- In computer graphics, it can be instantiated in order to be drawn several times in different locations in a scene which can improve the performance of rendering since a portion of the work needed to display each instance is reused.
- Program instance
- In a POSIX-oriented operating system, it refers to an executing process. It is instantiated for a program via system calls such as fork() and exec(). Each executing process is an instance of a program which it has been instantiated from.[2]
