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by peterfirefly 1149 days ago
And you can effectively do both:

    #ifdef NDEBUG
    #  define UNREACHABLE()   unreachable()
    #else
    #  define UNREACHABLE()   assert(0)
    #endif
That's what I have been doing for years, except with __builtin_unreachable()... and __assume(0) if I bothered to make it work under MSVC.
1 comments
pmarin 1149 days ago
And why this is not the default behaviur?

I am pretty sure many users are going to think it is correctness check an not an optimization attribute.

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dzaima 1149 days ago
I'd rather not have a basic feature be put behind needing to define an arbitrary NDEBUG; having to define your debugging setup around NDEBUG would not fit some things - e.g. in my case I'd end up having to always define NDEBUG, and continue with my own wrapper around things. (with <assert.h> you have the option of writing your own thing if you don't like its NDEBUG check, which is what I do; with unreachable(), if you literally cannot get its functionality other than NDEBUG, you're stuck with NDEBUG).
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peterfirefly 1149 days ago
Because C is a "do exactly as I say" language.
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