shared libraries

[utzoo!decvax!ucbvax!unix-wizards]

>From decvax!duke!unc!smb at Berkeley Sat Oct 31 17:44:47 1981
In-real-life: Steven M. Bellovin

Shared libraries can be implemented fairly cleanly, at the cost of
branching through a transfer vector.  That is, the first module of
the shared segment (and the only one directly addressable) contains
something like

	int (*list)()[] = {
		&printf,
		&scanf,
		NULL,
		&ctime,
		...

The order in this list would be fixed for all time, and the routine
actually linked in would branch indirectly through the start of
the shared module plus the proper offset.