Can I use my old a.out libraries to build ELF programs?
In general, yes, you may. You don’t need to use any special compiler or linker flags; just include the a.out objects or libraries as you would include ELF objects or libraries. However: • You can’t use an a.out object or library to create an ELF dynamically linked shared library. • System data structures in old libraries may not be compatible with data structures in new libraries. • The linker tries to convert a.out symbol names with initial underscores into ELF symbol names without initial underscores. An a.out assembler symbol without an initial underscore probably won’t link correctly. We can’t guarantee that this practice will always work, but our experience is that it usually does work. For example, X11 libraries will usually work, because the X11 interfaces have not changed significantly since earlier releases. On the other hand, routing and interface configuration information has changed since earlier releases in incompatible ways, so old libraries that handle routing or interfa
