Dependencies

In order to be able to construct projects efficiently, the IDE needs to know which components have been altered and so need to be rebuilt. This becomes very important as the size of projects grows; rebuilding everything each time you make a change to one file would be a waste of time.

Knowing which files need to be rebuilt is not trivial. There is no problem for files that have been altered since they were last built, but some files are not actually processed directly. The most obvious example would be a C header file. Changing a header file does not mean that the header file should be rebuilt, rather, any file that includes that header needs to be processed. The files that include the header are said to be dependent on the header file. The header file is known as a target file and the files depending on it are known as dependent files.