The linker searches for unresolved externals in the following order:
- Find all modules in the library that define current unresolved externals.
Process those modules (you may pickup more unresolved externals). The linker keeps making passes through that library until no new unresolved externals
are picked up.
- It then advances to the next library.
In a similar manner, the linker makes a pass through the entire set of libraries. After the last library is searched, if new unresolved externals have been
picked up, it returns to the first library and makes another pass.
Problems can be avoided if you do not use bidirectional cross-library references (that is, avoid library A calling something in library that calls something
else in library A). Try to make each library as self-contained as possible.