The word thunk has at least three related meanings in computing science. A “thunk” may be:
- A piece of code to perform a delayed computation (similar to a closure)
- A feature of some virtual function table implementations (similar to a wrapper function)
- A mapping of machine data from one system-specific form to another, usually for compatibility reasons
In all three senses, the word refers to a piece of low-level code, usually machine-generated, that implements some detail of a particular software system.
In this post (whose name looks like an unrelated typo) we shall observe the need for a thunk of the second kind, in C++.