gnatstub creates body stubs, that is, empty but compilable bodies for library unit declarations.
Note: to invoke gnatstub with a project file, use the gnat
driver (see The GNAT Driver and Project Files).
To create a body stub, gnatstub has to compile the library unit declaration. Therefore, bodies can be created only for legal library units. Moreover, if a library unit depends semantically upon units located outside the current directory, you have to provide the source search path when calling gnatstub, see the description of gnatstub switches below.
By default, all the program unit body stubs generated by gnatstub
raise the predefined Program_Error exception, which will catch
accidental calls of generated stubs. This behavior can be changed with
option --no-exception (see below).