Avoid compiler warnings #152
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Using an `unsigned int` in the function is safe as all values assigned to it are > 0. Furthermore, logically the function cannot return a value < 1, therefore it should return an `unsigned int` or maybe `std::size_t` (as it deals with calculating a number of bytes a certain element is long) instead of an `int`, but that would change the API & ABI.
…classes In the base class `EbmlElement` there's the `virtual operator const EbmlId &`. This one is overridden in derived classes in libmatroska (and in `EbmlDummy` as well) in order to return the EBML ID belonging to the concrete element's class in libmatroska. The classes in libmatroska don't derive directly from EbmlElement. Instead there's base-type-specific intermediate class (`EbmlUInteger`, `EBMLSInteger`, `EBMLString`, `EBMLUnicodeString`, `EbmlFloat`, `EbmlDate`). For example: `EbmlElement` ← `EbmlUInteger` ← `KaxTrackNumber` Some of these intermediate classes provide some non-`virtual` `operator`s themselves (e.g. an `operator std::uint64_t` for `EbmlUInteger`) but don't override the `virtual operator const EbmlId &` from the base class, `EbmlElement`. For regular functions this is a common mistake made by programmers, assuming that even though they're leaving out the `virtual` key word in the derived class the function from the derived class overrides the `virtual` function from the base class. However, due to different signatures they don't override; instead you now have two different functions in the same class. This is where the compiler comes in: `g++` 13.2.x emits a warning about this if the category `overloaded-virtual` is enabled. The fix is to tell the compiler that we're doing what we intend to here: we do not want to override the `virtual operator` from the base class; instead we intentionally introduce further, different non-`virtual` `operators`. We do this with a `using Base::operator …` directive.
robUx4
approved these changes
Dec 13, 2023
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I had only intended them for v2.x. They're just warnings, after all, and I don't plan on long-term maintenance for v1.x. Neither patch should break API or ABI, though. |
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Please read the commit messages. They explain in great detail what the warnings & fixes are about.