Why don’t languages raise errors on integer overflow by default?

In C#, it was a question of performance. Specifically, out-of-box benchmarking.

When C# was new, Microsoft was hoping a lot of C++ developers would switch to it. They knew that many C++ folks thought of C++ as being fast, especially faster than languages that “wasted” time on automatic memory management and the like.

Both potential adopters and magazine reviewers are likely to get a copy of the new C#, install it, build a trivial app that no one would ever write in the real world, run it in a tight loop, and measure how long it took. Then they’d make a decision for their company or publish an article based on that result.

The fact that their test showed C# to be slower than natively compiled C++ is the kind of thing that would turn people off C# quickly. The fact that your C# app is going to catch overflow/underflow automatically is the kind of thing that they might miss. So, it’s off by default.

I think it’s obvious that 99% of the time we want /checked to be on. It’s an unfortunate compromise.

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