alt Hacker NewsIt's an idiom for telling the compiler “don't give a warning on this argument not being used, I know about it”. Not all compilers will heed it. Other choices include e.g. __attribute__((unused)) (GNU), [[maybe_unused]] (C++17/C23) or just not giving it a name (nonstandard, but very commonly supported).
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zabzonk • 12/08/2024
OK, thank you. But why do the functions have those unused parameters?
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> or just not giving it a name (nonstandard, but very commonly supported)
It's only supported by gcc 11+ and clang 11+ (both from ~2021) because it was a suggested C2x extension. It's been accepted in C23 so other compilers will eventually support it, but I wouldn't hold my breath regarding when that happens.