[saynsedit]

Undefined behavior is one of the most intelligent things the C designers did when designing the language.

It's a fact of life that not all syntactic forms will have meaning. What's sqrt(-1)? Trick question, There's no meaningful answer (in terms of real numbers alone)! Why should anyone specify if it crashes the program, returns 0, throws an exception, etc.? Who cares? garbage in, garbage out.

Another example, "the floor had a pretty day with his melted spaceship" that is a grammatically well formed sentence but what does it mean? Don't answer that!

[loup-vaillant]

> Undefined behavior is one of the most intelligent things the C designers did when designing the language.

I agree, actually. They just went too far. Too many things are undefined for no good reason. Even sqrt(-1) is debatable, by the way: if your platform provides an efficient way to trap, it should probably trap, and the compiler should not assume it will never happen.

And if you want crazy optimizations, consider introducing unsafe assertions into the language. That is, arbitrary boolean expressions the compiler is allowed to assume will always return true.

[saynsedit]

I don't necessarily disagree that they went too far though I assume they probably had good reason at the time in most cases.

I'd prefer it if the decision to trap or not were an option to the compiler.

It would be nice if there were a GUARANTEE() macro so that the programmer could specify conditions that would never happen even in a production build like: GUARANTEE(n >= 0). Also if trapping was enabled, it would trap at runtime. This is a nice post about that idea http://blog.regehr.org/archives/1096