Can C++11 INVOKE be defined with C++98 compilers?
Hi, I would like to implement C++11 INVOKE on C++98 compilers. I have a C++11 implementation on boost/thread/detail/invoke.hpp based on the one of libc++. Could this be done or there is something that can not be done inherently? Best, Vicente
On Tue, Apr 9, 2013 at 11:02 PM, Vicente J. Botet Escriba < vicente.botet@wanadoo.fr> wrote:
Hi,
I would like to implement C++11 INVOKE on C++98 compilers.
I have a C++11 implementation on boost/thread/detail/invoke.hpp based on the one of libc++.
Could this be done or there is something that can not be done inherently?
Can you briefly describe what INVOKE does (or...should do)? - Jeff
Le 12/04/13 06:07, Jeffrey Lee Hellrung, Jr. a écrit :
On Tue, Apr 9, 2013 at 11:02 PM, Vicente J. Botet Escriba < vicente.botet@wanadoo.fr> wrote:
Hi,
I would like to implement C++11 INVOKE on C++98 compilers.
I have a C++11 implementation on boost/thread/detail/invoke.hpp based on the one of libc++.
Could this be done or there is something that can not be done inherently?
Can you briefly describe what INVOKE does (or...should do)?
Hi, from the standard http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3485.pdf 20.8.2 Requirements [func.require] 1 Define INVOKE(f, t1, t2, ..., tN) as follows: — (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T and t1 is an object of type T or a reference to an object of type T or a reference to an object of a type derived from T; — ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a class T and t1 is not one of the types described in the previous item; — t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is an object of type T or a reference to an object of type T or a reference to an object of a type derived from T; — (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1 is not one of the types described in the previous item; — f(t1, t2, ..., tN) in all other cases. 2 Define INVOKE(f, t1, t2, ..., tN, R) as INVOKE(f, t1, t2, ..., tN) implicitly converted to R The libc++ implementation is // __invoke // bullets 1 and 2 template <class _Fp, class _A0, class ..._Args> inline _LIBCPP_INLINE_VISIBILITY auto __invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args) -> decltype((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...)) { return (_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...); } template <class _Fp, class _A0, class ..._Args> inline _LIBCPP_INLINE_VISIBILITY auto __invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args) -> decltype(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...)) { return ((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...); } // bullets 3 and 4 template <class _Fp, class _A0> inline _LIBCPP_INLINE_VISIBILITY auto __invoke(_Fp&& __f, _A0&& __a0) -> decltype(_VSTD::forward<_A0>(__a0).*__f) { return _VSTD::forward<_A0>(__a0).*__f; } template <class _Fp, class _A0> inline _LIBCPP_INLINE_VISIBILITY auto __invoke(_Fp&& __f, _A0&& __a0) -> decltype((*_VSTD::forward<_A0>(__a0)).*__f) { return (*_VSTD::forward<_A0>(__a0)).*__f; } // bullet 5 template <class _Fp, class ..._Args> inline _LIBCPP_INLINE_VISIBILITY auto __invoke(_Fp&& __f, _Args&& ...__args) -> decltype(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...)) { return _VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...); } The result_of is defined as // __invokable template <class _Fp, class ..._Args> struct __invokable_imp : private __check_complete<_Fp> { typedef decltype( __invoke(_VSTD::declval<_Fp>(), _VSTD::declval<_Args>()...) ) type; static const bool value = !is_same<type, __nat>::value; }; template <class _Fp, class ..._Args> struct __invokable : public integral_constant<bool, __invokable_imp<_Fp, _Args...>::value> { }; // __invoke_of template <bool _Invokable, class _Fp, class ..._Args> struct __invoke_of_imp // false { }; template <class _Fp, class ..._Args> struct __invoke_of_imp<true, _Fp, _Args...> { typedef typename __invokable_imp<_Fp, _Args...>::type type; }; template <class _Fp, class ..._Args> struct __invoke_of : public __invoke_of_imp<__invokable<_Fp, _Args...>::value, _Fp, _Args...> { }; template <class _Fp, class ..._Args> class _LIBCPP_TYPE_VIS result_of<_Fp(_Args...)> : public __invoke_of<_Fp, _Args...> { };
On Thu, Apr 11, 2013 at 10:41 PM, Vicente J. Botet Escriba < vicente.botet@wanadoo.fr> wrote:
Le 12/04/13 06:07, Jeffrey Lee Hellrung, Jr. a écrit :
On Tue, Apr 9, 2013 at 11:02 PM, Vicente J. Botet Escriba < vicente.botet@wanadoo.fr> wrote:
Hi,
I would like to implement C++11 INVOKE on C++98 compilers.
I have a C++11 implementation on boost/thread/detail/invoke.hpp based on the one of libc++.
Could this be done or there is something that can not be done inherently?
Can you briefly describe what INVOKE does (or...should do)?
Hi,
from the standard http://www.open-std.org/JTC1/** SC22/WG21/docs/papers/2012/**n3485.pdf<http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3485.pdf>
20.8.2 Requirements [func.require] 1 Define INVOKE(f, t1, t2, ..., tN) as follows: — (t1.*f)(t2, ..., tN) when f is a pointer to a member function of a class T and t1 is an object of type T or a reference to an object of type T or a reference to an object of a type derived from T;
— ((*t1).*f)(t2, ..., tN) when f is a pointer to a member function of a class T and t1 is not one of the types described in the previous item;
— t1.*f when N == 1 and f is a pointer to member data of a class T and t1 is an object of type T or a reference to an object of type T or a reference to an object of a type derived from T;
— (*t1).*f when N == 1 and f is a pointer to member data of a class T and t1 is not one of the types described in the previous item;
— f(t1, t2, ..., tN) in all other cases. 2 Define INVOKE(f, t1, t2, ..., tN, R) as INVOKE(f, t1, t2, ..., tN) implicitly converted to R
Got it.
The libc++ implementation is
// __invoke
// bullets 1 and 2
template <class _Fp, class _A0, class ..._Args> inline _LIBCPP_INLINE_VISIBILITY auto __invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args) -> decltype((_VSTD::forward<_A0>(**__a0).*__f)(_VSTD::forward<_** Args>(__args)...)) { return (_VSTD::forward<_A0>(__a0).*__**f)(_VSTD::forward<_Args>(__** args)...); }
[...] I glanced at your implementation in thread/detail, and noticed you had replaced the &&'s with BOOST_THREAD_RV_REF's, which I don't think is right in C++03... In C++03, you might be able to get away with defining an INVOKE (variadic) macro that does what you want...? Hmmm...thinking about it a bit, the difference between the pointer-to-member-function case and function object/pointer case makes that tricky. Maybe the best you can do in C++03 is imperfect forwarding with multiple overloads for each arity + invokable-type combination :( - Jeff
Le 12/04/13 07:41, Vicente J. Botet Escriba a écrit :
Le 12/04/13 06:07, Jeffrey Lee Hellrung, Jr. a écrit :
On Tue, Apr 9, 2013 at 11:02 PM, Vicente J. Botet Escriba < vicente.botet@wanadoo.fr> wrote:
Hi,
I would like to implement C++11 INVOKE on C++98 compilers.
I have a C++11 implementation on boost/thread/detail/invoke.hpp based on the one of libc++.
Could this be done or there is something that can not be done inherently?
Can you briefly describe what INVOKE does (or...should do)?
Hi,
from the standard http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2012/n3485.pdf
You could also be interested in this thread if you have access [c++std-lib-33032] Re: std::result_of and ill-formed call expressions Vicente
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Jeffrey Lee Hellrung, Jr. -
Vicente J. Botet Escriba