The only way UTF-8 affects std::string is that size(), length(), and all the indices are measured in bytes, not characters. And, as sbi points out, incrementing the iterator provided by std::string will step forward by byte, not by character, so it can actually point into the middle of a multibyte UTF-8 codepoint. There’s no UTF-8-aware …
As infrastructure I was using llvm/clang 3.0 along with the llvm std c++ library within XCode4. Well that appears to be your problem. The C++11 standard states the following requirements for make_shared<T> (and allocate_shared<T>), in section 20.7.2.2.6: Requires: The expression ::new (pv) T(std::forward(args)…), where pv has type void* and points to storage suitable to hold …
I don’t think this is a bug. If you change the constexpr to const, it still fails, with the exact same error. You’ve declared S::X, but not defined it anywhere, so there’s no storage for it. If you do anything with it that needs to know the address of it then you’ll need to define …
Here is the implementation used by g++ 4.6.1: _GLIBCXX_WEAK_DEFINITION void * operator new (std::size_t sz) throw (std::bad_alloc) { void *p; /* malloc (0) is unpredictable; avoid it. */ if (sz == 0) sz = 1; p = (void *) malloc (sz); while (p == 0) { new_handler handler = __new_handler; if (! handler) #ifdef __EXCEPTIONS …
VC6 was non-compliant by default in this regard. VC6’s new returned 0 (or NULL). Here’s Microsoft’s KB Article on this issue along with their suggested workaround using a custom new handler: Operator new does not throw a bad_alloc exception on failure in Visual C++ If you have old code that was written for VC6 behavior, …
Why must I provide operator== when operator<=> is enough? Well, mainly because it’s not enough 🙂 Equality and ordering are different buckets when it comes time for C++ to rewrite your statements: Equality Ordering Primary == <=> Secondary != <, >, <=, >= Primary operators have the ability to be reversed, and secondary operators have …
This works for me in MSVC10 int x = 5; auto del = [](int * p) { std::cout << “Deleting x, value is : ” << *p; }; std::unique_ptr<int, decltype(del)> px(&x, del); And on gcc 4.5, here I’ll skip going to the standard, unless you don’t think that example is doing exactly what you’d expect …
Dereferencing the pointer doesn’t create a copy; it creates an lvalue that refers to the pointer’s target. This can be bound to the lvalue reference argument, and so the function receives a reference to the object that the pointer points to, and returns a reference to the same. This behaviour is well-defined, and no temporary …
I’m coming to this party late, and offering an additional answer because I do not believe any other answer at this time is completely correct. Question: Is a moved-from vector always empty? Answer: Usually, but no, not always. The gory details: vector has no standard-defined moved-from state like some types do (e.g. unique_ptr is specified …
In C++11: for (bool b : { false, true }) { /* … */ } Here’s a C++03 version: for (bool a = true, b = false; b != a; a = a && b, b = !b) { /*…*/ } (Use either a or b.)