Projects
In IDL, a project is a directory that contains source code files and other resources (data, image files, documentation, and so on). Projects are especially useful as logical containers for related source code and resource files. A project is saved within the IDL workspace, which is a directory that contains project directories, metadata about the contained projects, and information about the state of the IDL Workbench.
While you can build and run individual .pro files, you can also build and run an entire project, as well as configure how the project is built. These options are located on the project properties dialog, which is referenced by selecting the project in the Project Explorer view and selecting Project → Properties on the main menu bar.
Projects are described in more detail in Projects and Workspaces. For a tutorial on using projects, see Working with Projects.