For example, if the folder C:\temp\sources should be linked in an imported project and we have defined the path variable DEVEL_ROOT_DIR with the value C:\temp, then that folder will be linked as DEVEL_ROOT_DIR/sources and the DEVEL_ROOT_DIR path variable will be created in the workspace. If such a variable cannot be used (for example, because its value points to another folder not containing C:\temp\sources folder, it is already defined and has different value, or it has an invalid value), then C:\temp\sources folder will be linked using the full path C:\temp\sources.