Le 13/01/13 11:09, Andrey Semashev a écrit :
On Sunday 13 January 2013 00:15:23 Vicente J. Botet Escriba wrote:
Le 12/01/13 19:50, Andrey Semashev a écrit :
On January 12, 2013 9:57:22 PM "Vicente J. Botet Escriba"
Andrey, the provided patch goes too far for what I was expecting. You have made a lot of changes, C++11 interface has not been preserved, and I'm not sure the algorithm is the same. The algorithm is different for sure. What exactly do you mean by C++11 interface? Does C++11 have call_once? The only C++11 thing I saw was
<vicente.botet@wanadoo.fr> wrote: the once_flag definition which gave no apparent benefits. C++11 defines the following interface. There is no STD_ONCE_INIT initializer.
struct once_flag { constexpr once_flag() noexcept; once_flag(const once_flag&) = delete; once_flag& operator=(const once_flag&) = delete; }; template<class Callable, class ...Args> void call_once(once_flag& flag, Callable func, Args&&... args);
Could this once_flag be implemented using the trick you used to mask the atomic dependency on the header file? Hmm, I didn't know the standard defined call_once.
It is possible to define once_flag as defined by the standard.
But the previous implementation seem incorrect to me. once_flag *must* be either POD or have a constexpr default constructor while the previous code (as well as the code in win32/once.hpp) uses BOOST_CONSTEXPR which can be empty. BOOST_THREAD_PROVIDES_ONCE_CXX11 macro doesn't depend on constexpr or noexcept availability so it can't be used to enable C++11 implementation. Andrey, could you explain me why once_flag must be either be a POD or follow strictly the C++11 interface? In other words, what are the
Could you work on complementing your patch to take care of the C++11 interface? problems defining it as follows? struct once_flag { once_flag(); private: once_flag(const once_flag&); once_flag& operator=(const once_flag&); }; Best, Vicente