Integer overflow in C: standards and compilers

Question

Edited to include proper standard reference thanks to Carl Norum.

The C standard states

If an exceptional condition occurs d

Answer 1

For completeness, I'd like to add that Clang now has "checked arithmetic builtins" as a language extension. Here is an example using checked unsigned multiplication:

unsigned x, y, result;
...
if (__builtin_umul_overflow(x, y, &result)) {
    /* overflow occured */
    ...
}
...

http://clang.llvm.org/docs/LanguageExtensions.html#checked-arithmetic-builtins