Alberto Barbati <abarbati@iaanus.com> writes:
Ah! And there's one more case in which we are helpless, although I'm curious to see an implementation that exploits such latitude: the wording used in the standard does not guarantee that the mapping from pointers to integers always produce the same value over time. In other words:
char* p = new char; size_t i1 = reinterpret_cast<size_t>(p); size_t i2 = reinterpret_cast<size_t>(p); assert(i1 == i2); // ??? char* q1 = reinterpret_cast<char*>(i1); char* q2 = reinterpret_cast<char*>(i2); assert(p == q1 && q1 == q2);
The standard guarantees that the second assert passes, but says nothing about the first assert.
There are other cases too. reinterpret_cast could map all pointers to the same integer. I'm saying what Peter's saying. This is non-portable territory; don't lose sleep over it; practically speaking it will work most places; everywhere else we'll fix it. -- Dave Abrahams Boost Consulting www.boost-consulting.com