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This isn't a language-lawyer kind of thing, and, as I said, I don't think C++ features or GNU extensions will help. The pre-defining extern functions approach
by kragen 2y ago
This isn't a language-lawyer kind of thing, and, as I said, I don't think C++ features or GNU extensions will help. The pre-defining extern functions approach will get you a finite number of tries, but I suppose it could be a fairly large finite number.
If for some reason I had to solve this problem in real life I would do it with a postprocesing step like your #1 suggestion. But once you're putting code into your Makefile anything goes.
- Y_Y 2y agoYou can just append a function with __attribute__((constructor)) if GNU extensions are allowed and that will run before main and let you mess with the function pointers.
- kragen 2y agoIn an undefined order?
- Y_Y 2y agoObjection! Badgering the witness! I'm sure you know, but the undefined order is easily fixed by e.g. keeping a priority queue for your appended functions and then each time you add one you can include a constructor that enters it in the queue with a priority corresponding to its desired position.
- kragen 2y agoAnd then main() pops the latest override off the priority queue? I guess you're right; GCC extensions do solve the problem. And you can do the same thing with static object constructors in C++, though language-lawyeringly I'm not sure the standard guarantees enough about static initialization order to give the first constructor a well-defined empty queue.