A programming language is said to have first-class functions when it provides the capability of manipulating functions in the same way as other values, i.e., storing in variables, passing as parameters, etc.. Programming with first-class functions opens the programmer to new forms of abstractions and it s the default in functional programming languages. However, in the realm of imperative languages (including object-oriented languages), each language has different semantics, properties, and terminology for functions—in great part, thanks to their focus on mutability, which isn t present in functional languages. To help shed light on these differences, we made a survey of the specifi-cation of function values in imperative programming languages from many different disciplines. For each language, we illustrate, based on examples,the properties of function values in it, highlighting where it differs from other languages—all this with a consistent terminology in all languages. We provide a reference that compares and contrasts different renditions offunctions in one single place and conclude that the design of functions in a language depends on the interaction of its features and constraints with its functions.