smathew
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Linking libraries
Why is that the order in which the libraries are linked does matter ?. Otherwise, a symbol referencing error occurs !!!
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Thanks josv for the detailed explaination.
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Moondancer
Moderator @ Experts Exchange
Moondancer
Moderator @ Experts Exchange
Traditionally, Unix uses a one-pass linker. That is, the linker goes through the list of objects and libraries only once. Whenever it encounters and object, it adds that to the executable image. Any unresolved references in that object are added to the global list of "references still to be resolved".
If the linker encounters a library, it sees which objects it must pull from the library, and add to the image. Only objects that are necessary to solve one or more of the currently known unresolved references are retrieved from the library. Any unresolved references in the objects pulled from the library are added to the unresolved reference list.
(Unix has a tool called "lorder" that can be used in combination with ar to sort the objects in a library in reference->referenced order.
If the linker then goes on and encounters another object that needs a reference from a a library that it has already processed, tough luck!
I know that modern linkers repeat the searching through the libraries until they have either resolved all references, or references remain unresolved (i.e. are not in any of the libraries).
++Jos