Re:Defining the Undefinedness of C (2015) [pdf]
by nayuki on Wednesday July 26, 2017 @06:50PM
(#14861105)
The silver lining in that Java bug is that it is guaranteed to compute the same wrong negative indexes every time on every platform, and it is guaranteed to throw ArrayIndexOutOfBoundsException when the array is attempted to be indexed. Though the code is wrong, it is at least consistently wrong and loudly wrong. The same cannot be said for a similar bug implemented in C.
Re:Defining the Undefinedness of C (2015) [pdf]
by littlestymaar on Thursday July 27, 2017 @10:23AM
(#14865523)
Well nobody prevents you from writing a compiler that will have this exact same behavior for the C language. In practice it doesn't happen because this «good citizen» compiler will produce code being slower than GCC or Clang on all benchmark, and since nowadays people mostly use C when performance is critical, this compiler will not be used by anyone.
Why even bother writing C if you all you achieve is Java, PyPy or JavaScript level in term of performance ?
Reminds me of the Java binary search bug: https://research.googleblog.com/2006/06/extra-extra-read-all...
I think the correct code here would be something like:
Or something like that. Obviously that's rather awkward, with the risk of a sneaky off-by-one bug. (Edit to add: heh, just noticed I'm assuming max+1 won't overflow!) It would be great to have a C-like language that encourages safer code like that.