Strengthen your programming skills with tips and techniques from the experts
![On passing a list to a SAS/IML module](https://blogs.sas.com/content/iml/files/2017/01/ProgrammingTips-2.png)
SAS/IML programmers often create and call user-defined modules. Recall that a module is a user-defined subroutine or function. A function returns a value; a subroutine can change one or more of its input arguments. I have written a complete guide to understanding SAS/IML modules, which contains many tips for working