On 27/11/2019 21:27, Ryan Joseph via fpc-pascal wrote: >> On Nov 27, 2019, at 2:22 PM, Jonas Maebe <jo...@freepascal.org> wrote: >> >> There is no tool that can show this, because a static library is just a >> collection of random object files. It does not contain any metadata >> about where these symbols are supposed to come from (and they could in >> fact come from anywhere, be it individual object files, object files >> collected in another static library, or a dynamic library). > That's what I had originally thought. Can static libraries have dependancies > on other static libraries?
Again, a static library has no dependencies because it is literally just a collection of object files. They're packed like a zipfile into a single file for convenience, but that's it. Those object files can contain references to symbols that are not defined in that same collection of object files, but I mentioned above already that those symbols can come from anywhere. It's like saying that an object file has a dependency on a library. It never has. It just references external symbols, which in turn could be defined anywhere. The only thing that can depend on a (by definition dynamic (*) ) library, is an executable or dynamic library (or their kin, like frameworks and dylib bundles on macOS). This happens when the static linker, while looking for those undefined symbols, at link time discovers that they happen to be defined in a dynamic library. In that case, it will store a reference to that dynamic library in the generated executable/dynamic library to indicate to the dynamic linker where it should look for external symbols. > I noticed that when I linked a 12MB library my final binary was only 5MB so I > presume there were duplicate symbols that were ignored. Code and data that are defined in object files (in turnoptionally contained in static libraries), but that are not referenced any other code part of the linking proceess, are simply not linked/included into your binary (unless you explicitly force linking everything from a referenced static library/object file). Jonas (*) On some platforms, like AIX, the situation is a bit more blurry, but the main concept holds. _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
