Because you can reuse build files for programs, subprojects, and libraries in multiple projects, it is important to specify whether the options for a build file are specific to the current project or whether the options are specific to the build file itself regardless of what project it belongs to. This choice, which is based on which build file is the base project, determines if the options are stored in the build file itself or in its parent's build file. For more information about the Builder's base project, see "Navigating through your project".
Options set in this way are stored in the parent's build file (in this example, masterfoo.bld). If you reuse the child's build file in a different project, the options will not be carried over into the new project.
Options set in the way are stored as part of the child's build file (in this example, foochild.bld), and therefore will be set for that build file regardless of what parent it belongs to.