[jerf]

You just destroyed all C code in the world. At that level of paranoia, you've basically defined a brand new language, and if you're going to do that, why make it C at all?

Smart people with a ton of experience in C have already examined the possibility of defining a C dialect with much less undefined behavior in it. In fact, I believe it's been seriously tried more than once by independent groups. And the result has been the same each time; initial excitement and optimism gives way to total failure. It's simply way too deeply ingrained in the definition of C, backed by all the code in the world written in C. If you want less undefined behavior, your only choice is to leave C.

[wamaral]

OP was talking about a compiler option, that most likely would not break anything unless you enable the flag.

As for choice, I'll take "here's what happens" vs "your code is in the hands of fate now" any day. Glad we do have choice.