a is not constant expression(see standard quote below) and therefore: a || 1 Is not a constant expression either, although we know the expression has to evaluate to true the standard requires left to right evaluation here and I see no exceptions that would allow the compiler to skip the lvalue-to-rvalue conversion of a. but: … Read more
It’s a bit more complicated. In C++03 and C++11, &var is a constant expression if var is a local static / class static or namespace scope variable. This is called an address constant expression. Initializing a class static or namespace scope pointer variable with that constant expression is guaranteed to be done before any code … Read more
As T.C. demonstrated with some links in a comment, the standard is not quite clear on this; a similar problem arises with trailing return types using decltype(memberfunction()). The central problem is that class members are generally not considered to be declared until after the class in which they’re declared is complete. Thus, regardless of the … Read more
Yes, division by zero is undefined behavior and neither the C nor C++ standard impose any requirements in such cases. Although in this case I believe you should at least issue a diagnostic(see below). Before I go quoting the standards, I should note that although this may be conformant behavior quality of implementation is a … Read more