Tell HN: C Experts Panel – Ask us anything about C

Re:Tell HN: C Experts Panel – Ask us anything about C by alerighi on Tuesday April 14, 2020 @11:16AM (#22867000)

The compiler assumes that the loop will alwasy terminate and that assumption is wrong, because in reality there is the possibility that the loop will not terminate, since the hardware WILL overflow.

So it's not the best solution. If we want to make this behaviour for optimizations (that are to me not worthed, giving the risk of potentially critical bugs) we must make that behavior explicit, not implicit: thus is the programmer that has to say to the compiler, I guarantee you that this operation will never overflow, if it does it's my fault.

We can agree that having a number that wraps around is not a particularly good choice. But unless we convince Intel in some way that this is bad and make the CPU trap on an overflow, so we can catch that bug, this is the behaviour that we have because is the behaviour of the hardware.

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Re:Tell HN: C Experts Panel – Ask us anything about C by klodolph on Tuesday April 14, 2020 @12:01PM (#22867579)

> The compiler assumes that the loop will alwasy terminate and that assumption is wrong, because in reality there is the possibility that the loop will not terminate, since the hardware WILL overflow.

The language is not a model of hardware, nor should it be. If you want to write to the hardware, the only option continues to be assembly.

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Re:Tell HN: C Experts Panel – Ask us anything about C by coliveira on Tuesday April 14, 2020 @12:17PM (#22867784)

> I guarantee you that this operation will never overflow, if it does it's my fault.

This is exactly what every C programmer does, all the time.

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