On Tue, Nov 11, 2008 at 08:43:40PM -0800, James Dennett wrote: > (There are secondary uses of unions for type punning. Most such uses > are not valid portable C++, but g++ supports them because they're so > common in real code.)
On the contrary: the uses of unions for type-punning, while not portable, are valid C++, and while not portable, the behavior is implementation-defined (because it exposes the bitwise implementation of C and C++ types). Without this feature, it would not be possible to implement a function like ldexp or frexp in C or C++, where we want to consider the same storage either as a double or as a sequence of bytes. This doesn't change your main point: asking that the compiler support initializers for more than one element of a union makes no sense.
