Question

What is the difference between static library and relocatable object file? Or between dynamic library and shared object file.

And if it’s not equal things, what have dynamic library, that allows to link with it, but shared object file doesn’t?

Answer 1

A static library is basically just a collection of object files. It’s typically just an ar archive of object files. Using ar, you can extract object files from the library, add different object files to it, etc.

Generally speaking, the difference between a dynamic library and a shared object file is the target — Windows uses dynamic libraries, Linux uses shared objects. There is a little more difference than that, but not a whole lot.