next: drop CV_CXX11 conditions

define itself is still here for compatibility

modules/core/include/opencv2/core/cuda/functional.hpp

@@ -58,7 +58,6 @@
 namespace cv { namespace cuda { namespace device
 {
     // Function Objects
-#ifdef CV_CXX11
     template<typename Argument, typename Result> struct unary_function
     {
         typedef Argument argument_type;
@@ -70,10 +69,6 @@ namespace cv { namespace cuda { namespace device
         typedef Argument2 second_argument_type;
         typedef Result result_type;
     };
-#else
-    template<typename Argument, typename Result> struct unary_function : public std::unary_function<Argument, Result> {};
-    template<typename Argument1, typename Argument2, typename Result> struct binary_function : public std::binary_function<Argument1, Argument2, Result> {};
-#endif
 
     // Arithmetic Operations
     template <typename T> struct plus : binary_function<T, T, T>

modules/core/include/opencv2/core/cvdef.h

@@ -417,6 +417,9 @@ Cv64suf;
 #    undef CV_CXX11
 #  endif
 #endif
+#ifndef CV_CXX11
+#  error "OpenCV 4.x+ requires enabled C++11 support"
+#endif
 
 
 /****************************************************************************************\

modules/core/include/opencv2/core/mat.hpp

@@ -53,9 +53,7 @@
 
 #include "opencv2/core/bufferpool.hpp"
 
-#ifdef CV_CXX11
 #include <type_traits>
-#endif
 
 namespace cv
 {
@@ -984,7 +982,6 @@ public:
     */
     template<typename _Tp> explicit Mat(const std::vector<_Tp>& vec, bool copyData=false);
 
-#ifdef CV_CXX11
     /** @overload
     */
     template<typename _Tp, typename = typename std::enable_if<std::is_arithmetic<_Tp>::value>::type>
@@ -993,7 +990,6 @@ public:
     /** @overload
     */
     template<typename _Tp> explicit Mat(const std::initializer_list<int> sizes, const std::initializer_list<_Tp> list);
-#endif
 
 #ifdef CV_CXX_STD_ARRAY
     /** @overload
@@ -2210,10 +2206,8 @@ public:
     explicit Mat_(const Point3_<typename DataType<_Tp>::channel_type>& pt, bool copyData=true);
     explicit Mat_(const MatCommaInitializer_<_Tp>& commaInitializer);
 
-#ifdef CV_CXX11
     Mat_(std::initializer_list<_Tp> values);
     explicit Mat_(const std::initializer_list<int> sizes, const std::initializer_list<_Tp> values);
-#endif
 
 #ifdef CV_CXX_STD_ARRAY
     template <std::size_t _Nm> explicit Mat_(const std::array<_Tp, _Nm>& arr, bool copyData=false);

modules/core/include/opencv2/core/mat.inl.hpp

@@ -574,7 +574,6 @@ Mat::Mat(const std::vector<_Tp>& vec, bool copyData)
         Mat((int)vec.size(), 1, traits::Type<_Tp>::value, (uchar*)&vec[0]).copyTo(*this);
 }
 
-#ifdef CV_CXX11
 template<typename _Tp, typename> inline
 Mat::Mat(const std::initializer_list<_Tp> list)
     : Mat()
@@ -594,7 +593,6 @@ Mat::Mat(const std::initializer_list<int> sizes, const std::initializer_list<_Tp
     CV_Assert(size_total == list.size());
     Mat((int)sizes.size(), (int*)sizes.begin(), traits::Type<_Tp>::value, (uchar*)list.begin()).copyTo(*this);
 }
-#endif
 
 #ifdef CV_CXX_STD_ARRAY
 template<typename _Tp, std::size_t _Nm> inline
@@ -1634,7 +1632,6 @@ Mat_<_Tp>::Mat_(const std::vector<_Tp>& vec, bool copyData)
     : Mat(vec, copyData)
 {}
 
-#ifdef CV_CXX11
 template<typename _Tp> inline
 Mat_<_Tp>::Mat_(std::initializer_list<_Tp> list)
     : Mat(list)
@@ -1644,7 +1641,6 @@ template<typename _Tp> inline
 Mat_<_Tp>::Mat_(const std::initializer_list<int> sizes, std::initializer_list<_Tp> list)
     : Mat(sizes, list)
 {}
-#endif
 
 #ifdef CV_CXX_STD_ARRAY
 template<typename _Tp> template<std::size_t _Nm> inline

modules/core/include/opencv2/core/matx.hpp

@@ -53,9 +53,7 @@
 #include "opencv2/core/traits.hpp"
 #include "opencv2/core/saturate.hpp"
 
-#ifdef CV_CXX11
 #include <initializer_list>
-#endif
 
 namespace cv
 {
@@ -141,9 +139,7 @@ public:
          _Tp v12, _Tp v13, _Tp v14, _Tp v15); //!< 1x16, 4x4 or 16x1 matrix
     explicit Matx(const _Tp* vals); //!< initialize from a plain array
 
-#ifdef CV_CXX11
     Matx(std::initializer_list<_Tp>); //!< initialize from an initializer list
-#endif
 
     static Matx all(_Tp alpha);
     static Matx zeros();
@@ -361,9 +357,7 @@ public:
     Vec(_Tp v0, _Tp v1, _Tp v2, _Tp v3, _Tp v4, _Tp v5, _Tp v6, _Tp v7, _Tp v8, _Tp v9, _Tp v10, _Tp v11, _Tp v12, _Tp v13); //!< 14-element vector constructor
     explicit Vec(const _Tp* values);
 
-#ifdef CV_CXX11
     Vec(std::initializer_list<_Tp>);
-#endif
 
     Vec(const Vec<_Tp, cn>& v);
 
@@ -665,7 +659,6 @@ Matx<_Tp, m, n>::Matx(const _Tp* values)
     for( int i = 0; i < channels; i++ ) val[i] = values[i];
 }
 
-#ifdef CV_CXX11
 template<typename _Tp, int m, int n> inline
 Matx<_Tp, m, n>::Matx(std::initializer_list<_Tp> list)
 {
@@ -676,7 +669,6 @@ Matx<_Tp, m, n>::Matx(std::initializer_list<_Tp> list)
         val[i++] = elem;
     }
 }
-#endif
 
 template<typename _Tp, int m, int n> inline
 Matx<_Tp, m, n> Matx<_Tp, m, n>::all(_Tp alpha)
@@ -1019,11 +1011,9 @@ template<typename _Tp, int cn> inline
 Vec<_Tp, cn>::Vec(const _Tp* values)
     : Matx<_Tp, cn, 1>(values) {}
 
-#ifdef CV_CXX11
 template<typename _Tp, int cn> inline
 Vec<_Tp, cn>::Vec(std::initializer_list<_Tp> list)
     : Matx<_Tp, cn, 1>(list) {}
-#endif
 
 template<typename _Tp, int cn> inline
 Vec<_Tp, cn>::Vec(const Vec<_Tp, cn>& m)

modules/core/include/opencv2/core/utility.hpp

@@ -56,9 +56,7 @@
 #include "opencv2/core.hpp"
 #include <ostream>
 
-#ifdef CV_CXX11
 #include <functional>
-#endif
 
 namespace cv
 {
@@ -531,7 +529,6 @@ public:
 */
 CV_EXPORTS void parallel_for_(const Range& range, const ParallelLoopBody& body, double nstripes=-1.);
 
-#ifdef CV_CXX11
 class ParallelLoopBodyLambdaWrapper : public ParallelLoopBody
 {
 private:
@@ -551,7 +548,6 @@ inline void parallel_for_(const Range& range, std::function<void(const Range&)>
 {
     parallel_for_(range, ParallelLoopBodyLambdaWrapper(functor), nstripes);
 }
-#endif
 
 /////////////////////////////// forEach method of cv::Mat ////////////////////////////
 template<typename _Tp, typename Functor> inline