arrays - C++11 list initialization weird behaviour on Visual Studio 2013 -

i'm trying pass array function , prevent writing "std::unique_ptr" each time , make inline construction possible, introduce typedef (itemlist) alias array.

#include <iostream> #include <memory>  class base { public:     base()     {         std::cout << "base ctor" << std::endl;     };      virtual ~base()     {         std::cout << "base dtor" << std::endl;     }; };  typedef std::unique_ptr<base> itemlist[];  template<typename t> class derived : public base {     t val; public:     derived(t i)     {         val = i;         std::cout << "derived ctor" << val << std::endl;     };      ~derived()     {         std::cout << "derived dtor" << val << std::endl;     }; };  void dummyfunc(itemlist) {  }  void testfunc() {     dummyfunc(itemlist{         std::make_unique<derived<int>>(2),         std::make_unique<derived<float>>(3.0f)     }); }  //entry point int main() {     testfunc();     return 0; } 

this works intended in debug build , prints;

base ctor derived ctor2 base ctor derived ctor2 derived dtor2 base dtor derived dtor2 base dtor 

so far good. when build in release mode (with native compilers) get;

base ctor derived ctor2 base ctor derived ctor3 derived dtor2 base dtor 

the second item in array not getting destructed upon exiting lifecycle of array. way make work expect, using c++03 style initialization or debug mode;

itemlist tmplist = {     std::make_unique<derived<int>>(2),     std::make_unique<derived<float>>(2.0f) };  dummyfunc(tmplist); 

this results in intended behavior (all destructors called).

i have not tested other compiler yet expected behaviour? doing wrong or missing something?

update:

interestingly dtors called expected base instances;

dummyfunc(itemlist{     std::make_unique<base>(),     std::make_unique<base>() }); 

outputs;

base ctor base ctor base dtor base dtor 

and initializing array (without function call) behaves same function call.

your code not build g++ 6.2, , error explicit enough explain why don't expected behavior:

foo.cc:44:15: error: taking address of temporary array      dummyfunc(itemlist{                ^~~~~~~~~          std::make_unique<derived<int>>(2),          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~          std::make_unique<derived<float>>(3.0f)          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~      }); 

a simple fix use:

using itemlist = std::initializer_list<std::unique_ptr<base>>;

instead of array.

update: behavior of vs might correct one:

an lvalue or rvalue of type “array of n t” or “array of unknown bound of t” can converted prvalue of type “pointer t”. result pointer first element of array.