core: remove constructors from C API structures

POD structures can't have constructors.

modules/core/include/opencv2/core/types_c.h

@@ -44,6 +44,27 @@
 #ifndef OPENCV_CORE_TYPES_H
 #define OPENCV_CORE_TYPES_H
 
+#define CV__ENABLE_C_API_CTORS // enable C API ctors (must be removed)
+
+//#define CV__VALIDATE_UNUNITIALIZED_VARS 1  // C++11 & GCC only
+
+#ifdef __cplusplus
+
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
+#define CV_STRUCT_INITIALIZER {0,}
+#else
+#if defined(__GNUC__) && __GNUC__ == 4  // GCC 4.x warns on "= {}" initialization, fixed in GCC 5.0
+#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
+#endif
+#define CV_STRUCT_INITIALIZER {}
+#endif
+
+#else
+#define CV_STRUCT_INITIALIZER {0}
+#endif
+
+
 #ifdef HAVE_IPL
 #  ifndef __IPL_H__
 #    if defined _WIN32
@@ -285,6 +306,11 @@ CV_INLINE double cvRandReal( CvRNG* rng )
 #define IPL_BORDER_REFLECT    2
 #define IPL_BORDER_WRAP       3
 
+#ifdef __cplusplus
+typedef struct _IplImage IplImage;
+CV_EXPORTS _IplImage cvIplImage(const cv::Mat& m);
+#endif
+
 /** The IplImage is taken from the Intel Image Processing Library, in which the format is native. OpenCV
 only supports a subset of possible IplImage formats, as outlined in the parameter list above.
 
@@ -294,9 +320,6 @@ hand, the Intel Image Processing Library processes the area of intersection betw
 destination images (or ROIs), allowing them to vary independently.
 */
 typedef struct
-#ifdef __cplusplus
-  CV_EXPORTS
-#endif
 _IplImage
 {
     int  nSize;             /**< sizeof(IplImage) */
@@ -330,13 +353,22 @@ _IplImage
                                (not necessarily aligned) -
                                needed for correct deallocation */
 
-#ifdef __cplusplus
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     _IplImage() {}
-    _IplImage(const cv::Mat& m);
+    _IplImage(const cv::Mat& m) { *this = cvIplImage(m); }
 #endif
 }
 IplImage;
 
+CV_INLINE IplImage cvIplImage()
+{
+#if !defined(CV__ENABLE_C_API_CTORS)
+    IplImage self = CV_STRUCT_INITIALIZER; self.nSize = sizeof(IplImage); return self;
+#else
+    return _IplImage();
+#endif
+}
+
 typedef struct _IplTileInfo IplTileInfo;
 
 typedef struct _IplROI
@@ -460,13 +492,10 @@ typedef struct CvMat
     int cols;
 #endif
 
-
-#ifdef __cplusplus
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvMat() {}
-    CvMat(const CvMat& m) { memcpy(this, &m, sizeof(CvMat));}
-    CvMat(const cv::Mat& m);
+    CvMat(const cv::Mat& m) { *this = cvMat(m); }
 #endif
-
 }
 CvMat;
 
@@ -529,15 +558,8 @@ CV_INLINE CvMat cvMat( int rows, int cols, int type, void* data CV_DEFAULT(NULL)
 }
 
 #ifdef __cplusplus
-inline CvMat::CvMat(const cv::Mat& m)
-{
-    CV_DbgAssert(m.dims <= 2);
-    *this = cvMat(m.rows, m.dims == 1 ? 1 : m.cols, m.type(), m.data);
-    step = (int)m.step[0];
-    type = (type & ~cv::Mat::CONTINUOUS_FLAG) | (m.flags & cv::Mat::CONTINUOUS_FLAG);
-}
 
-inline CvMat cvMat(const cv::Mat& m)
+CV_INLINE CvMat cvMat(const cv::Mat& m)
 {
     CvMat self;
     CV_DbgAssert(m.dims <= 2);
@@ -546,7 +568,24 @@ inline CvMat cvMat(const cv::Mat& m)
     self.type = (self.type & ~cv::Mat::CONTINUOUS_FLAG) | (m.flags & cv::Mat::CONTINUOUS_FLAG);
     return self;
 }
+CV_INLINE CvMat cvMat()
+{
+#if !defined(CV__ENABLE_C_API_CTORS)
+    CvMat self = CV_STRUCT_INITIALIZER; return self;
+#else
+    return CvMat();
+#endif
+}
+CV_INLINE CvMat cvMat(const CvMat& m)
+{
+#if !defined(CV__ENABLE_C_API_CTORS)
+    CvMat self = CV_STRUCT_INITIALIZER; memcpy(&self, &m, sizeof(self)); return self;
+#else
+    return CvMat(m);
 #endif
+}
+
+#endif // __cplusplus
 
 
 #define CV_MAT_ELEM_PTR_FAST( mat, row, col, pix_size )  \
@@ -630,13 +669,15 @@ CV_INLINE int cvIplDepth( int type )
 
 #define CV_MAX_DIM            32
 
+#ifdef __cplusplus
+typedef struct CvMatND CvMatND;
+CV_EXPORTS CvMatND cvMatND(const cv::Mat& m);
+#endif
+
 /**
   @deprecated consider using cv::Mat instead
   */
 typedef struct
-#ifdef __cplusplus
-  CV_EXPORTS
-#endif
 CvMatND
 {
     int type;
@@ -661,13 +702,23 @@ CvMatND
     }
     dim[CV_MAX_DIM];
 
-#ifdef __cplusplus
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvMatND() {}
-    CvMatND(const cv::Mat& m);
+    CvMatND(const cv::Mat& m) { *this = cvMatND(m); }
 #endif
 }
 CvMatND;
 
+
+CV_INLINE CvMatND cvMatND()
+{
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvMatND self = CV_STRUCT_INITIALIZER; return self;
+#else
+    return CvMatND();
+#endif
+}
+
 #define CV_IS_MATND_HDR(mat) \
     ((mat) != NULL && (((const CvMatND*)(mat))->type & CV_MAGIC_MASK) == CV_MATND_MAGIC_VAL)
 
@@ -684,11 +735,7 @@ CvMatND;
 
 struct CvSet;
 
-typedef struct
-#ifdef __cplusplus
-  CV_EXPORTS
-#endif
-CvSparseMat
+typedef struct CvSparseMat
 {
     int type;
     int dims;
@@ -703,13 +750,13 @@ CvSparseMat
     int size[CV_MAX_DIM];
 
 #ifdef __cplusplus
-    void copyToSparseMat(cv::SparseMat& m) const;
+    CV_EXPORTS void copyToSparseMat(cv::SparseMat& m) const;
 #endif
 }
 CvSparseMat;
 
 #ifdef __cplusplus
-    CV_EXPORTS CvSparseMat* cvCreateSparseMat(const cv::SparseMat& m);
+CV_EXPORTS CvSparseMat* cvCreateSparseMat(const cv::SparseMat& m);
 #endif
 
 #define CV_IS_SPARSE_MAT_HDR(mat) \
@@ -796,10 +843,23 @@ typedef struct CvRect
     int width;
     int height;
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvRect() __attribute__(( warning("Non-initialized variable") )) {};
+    template<typename _Tp> CvRect(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 4);
+        x = y = width = height = 0;
+        if (list.size() == 4)
+        {
+            x = list.begin()[0]; y = list.begin()[1]; width = list.begin()[2]; height = list.begin()[3];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvRect(int _x = 0, int _y = 0, int w = 0, int h = 0): x(_x), y(_y), width(w), height(h) {}
     template<typename _Tp>
     CvRect(const cv::Rect_<_Tp>& r): x(cv::saturate_cast<int>(r.x)), y(cv::saturate_cast<int>(r.y)), width(cv::saturate_cast<int>(r.width)), height(cv::saturate_cast<int>(r.height)) {}
+#endif
+#ifdef __cplusplus
     template<typename _Tp>
     operator cv::Rect_<_Tp>() const { return cv::Rect_<_Tp>((_Tp)x, (_Tp)y, (_Tp)width, (_Tp)height); }
 #endif
@@ -809,16 +869,16 @@ CvRect;
 /** constructs CvRect structure. */
 CV_INLINE  CvRect  cvRect( int x, int y, int width, int height )
 {
-    CvRect r;
-
-    r.x = x;
-    r.y = y;
-    r.width = width;
-    r.height = height;
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvRect r = {x, y, width, height};
+#else
+    CvRect r(x, y , width, height);
+#endif
     return r;
 }
-
+#ifdef __cplusplus
+CV_INLINE CvRect cvRect(const cv::Rect& rc) { return cvRect(rc.x, rc.y, rc.width, rc.height); }
+#endif
 
 CV_INLINE  IplROI  cvRectToROI( CvRect rect, int coi )
 {
@@ -853,26 +913,28 @@ typedef struct CvTermCriteria
                      CV_TERMCRIT_EPS */
     int    max_iter;
     double epsilon;
-
-#ifdef __cplusplus
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvTermCriteria(int _type = 0, int _iter = 0, double _eps = 0) : type(_type), max_iter(_iter), epsilon(_eps)  {}
     CvTermCriteria(const cv::TermCriteria& t) : type(t.type), max_iter(t.maxCount), epsilon(t.epsilon)  {}
+#endif
+#ifdef __cplusplus
     operator cv::TermCriteria() const { return cv::TermCriteria(type, max_iter, epsilon); }
 #endif
-
 }
 CvTermCriteria;
 
 CV_INLINE  CvTermCriteria  cvTermCriteria( int type, int max_iter, double epsilon )
 {
-    CvTermCriteria t;
-
-    t.type = type;
-    t.max_iter = max_iter;
-    t.epsilon = (float)epsilon;
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvTermCriteria t = { type, max_iter, (float)epsilon};
+#else
+    CvTermCriteria t(type, max_iter, epsilon);
+#endif
     return t;
 }
+#ifdef __cplusplus
+CV_INLINE CvTermCriteria cvTermCriteria(const cv::TermCriteria& t) { return cvTermCriteria(t.type, t.maxCount, t.epsilon); }
+#endif
 
 
 /******************************* CvPoint and variants ***********************************/
@@ -882,10 +944,23 @@ typedef struct CvPoint
     int x;
     int y;
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvPoint() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvPoint(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 2);
+        x = y = 0;
+        if (list.size() == 2)
+        {
+            x = list.begin()[0]; y = list.begin()[1];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvPoint(int _x = 0, int _y = 0): x(_x), y(_y) {}
     template<typename _Tp>
     CvPoint(const cv::Point_<_Tp>& pt): x((int)pt.x), y((int)pt.y) {}
+#endif
+#ifdef __cplusplus
     template<typename _Tp>
     operator cv::Point_<_Tp>() const { return cv::Point_<_Tp>(cv::saturate_cast<_Tp>(x), cv::saturate_cast<_Tp>(y)); }
 #endif
@@ -895,24 +970,39 @@ CvPoint;
 /** constructs CvPoint structure. */
 CV_INLINE  CvPoint  cvPoint( int x, int y )
 {
-    CvPoint p;
-
-    p.x = x;
-    p.y = y;
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvPoint p = {x, y};
+#else
+    CvPoint p(x, y);
+#endif
     return p;
 }
-
+#ifdef __cplusplus
+CV_INLINE CvPoint cvPoint(const cv::Point& pt) { return cvPoint(pt.x, pt.y); }
+#endif
 
 typedef struct CvPoint2D32f
 {
     float x;
     float y;
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvPoint2D32f() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvPoint2D32f(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 2);
+        x = y = 0;
+        if (list.size() == 2)
+        {
+            x = list.begin()[0]; y = list.begin()[1];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvPoint2D32f(float _x = 0, float _y = 0): x(_x), y(_y) {}
     template<typename _Tp>
     CvPoint2D32f(const cv::Point_<_Tp>& pt): x((float)pt.x), y((float)pt.y) {}
+#endif
+#ifdef __cplusplus
     template<typename _Tp>
     operator cv::Point_<_Tp>() const { return cv::Point_<_Tp>(cv::saturate_cast<_Tp>(x), cv::saturate_cast<_Tp>(y)); }
 #endif
@@ -922,11 +1012,11 @@ CvPoint2D32f;
 /** constructs CvPoint2D32f structure. */
 CV_INLINE  CvPoint2D32f  cvPoint2D32f( double x, double y )
 {
-    CvPoint2D32f p;
-
-    p.x = (float)x;
-    p.y = (float)y;
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvPoint2D32f p = { (float)x, (float)y };
+#else
+    CvPoint2D32f p((float)x, (float)y);
+#endif
     return p;
 }
 
@@ -934,7 +1024,11 @@ CV_INLINE  CvPoint2D32f  cvPoint2D32f( double x, double y )
 template<typename _Tp>
 CvPoint2D32f cvPoint2D32f(const cv::Point_<_Tp>& pt)
 {
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvPoint2D32f p = { (float)pt.x, (float)pt.y };
+#else
     CvPoint2D32f p((float)pt.x, (float)pt.y);
+#endif
     return p;
 }
 #endif
@@ -948,10 +1042,11 @@ CV_INLINE  CvPoint2D32f  cvPointTo32f( CvPoint point )
 /** converts CvPoint2D32f to CvPoint. */
 CV_INLINE  CvPoint  cvPointFrom32f( CvPoint2D32f point )
 {
-    CvPoint ipt;
-    ipt.x = cvRound(point.x);
-    ipt.y = cvRound(point.y);
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvPoint ipt = { cvRound(point.x), cvRound(point.y) };
+#else
+    CvPoint ipt(cvRound(point.x), cvRound(point.y));
+#endif
     return ipt;
 }
 
@@ -962,10 +1057,23 @@ typedef struct CvPoint3D32f
     float y;
     float z;
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvPoint3D32f() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvPoint3D32f(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 3);
+        x = y = z = 0;
+        if (list.size() == 3)
+        {
+            x = list.begin()[0]; y = list.begin()[1]; z = list.begin()[2];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvPoint3D32f(float _x = 0, float _y = 0, float _z = 0): x(_x), y(_y), z(_z) {}
     template<typename _Tp>
     CvPoint3D32f(const cv::Point3_<_Tp>& pt): x((float)pt.x), y((float)pt.y), z((float)pt.z) {}
+#endif
+#ifdef __cplusplus
     template<typename _Tp>
     operator cv::Point3_<_Tp>() const { return cv::Point3_<_Tp>(cv::saturate_cast<_Tp>(x), cv::saturate_cast<_Tp>(y), cv::saturate_cast<_Tp>(z)); }
 #endif
@@ -975,31 +1083,51 @@ CvPoint3D32f;
 /** constructs CvPoint3D32f structure. */
 CV_INLINE  CvPoint3D32f  cvPoint3D32f( double x, double y, double z )
 {
-    CvPoint3D32f p;
-
-    p.x = (float)x;
-    p.y = (float)y;
-    p.z = (float)z;
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvPoint3D32f p = { (float)x, (float)y, (float)z };
+#else
+    CvPoint3D32f p((float)x, (float)y, (float)z);
+#endif
+    return p;
+}
 
+#ifdef __cplusplus
+template<typename _Tp>
+CvPoint3D32f cvPoint3D32f(const cv::Point3_<_Tp>& pt)
+{
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvPoint3D32f p  = { (float)pt.x, (float)pt.y, (float)pt.z };
+#else
+    CvPoint3D32f p((float)pt.x, (float)pt.y, (float)pt.z);
+#endif
     return p;
 }
+#endif
 
 
 typedef struct CvPoint2D64f
 {
     double x;
     double y;
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvPoint2D64f() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvPoint2D64f(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 2);
+        x = y = 0;
+        if (list.size() == 2)
+        {
+            x = list.begin()[0]; y = list.begin()[1];
+        }
+    };
+#endif
 }
 CvPoint2D64f;
 
 /** constructs CvPoint2D64f structure.*/
 CV_INLINE  CvPoint2D64f  cvPoint2D64f( double x, double y )
 {
-    CvPoint2D64f p;
-
-    p.x = x;
-    p.y = y;
-
+    CvPoint2D64f p = { x, y };
     return p;
 }
 
@@ -1009,18 +1137,25 @@ typedef struct CvPoint3D64f
     double x;
     double y;
     double z;
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvPoint3D64f() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvPoint3D64f(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 3);
+        x = y = z = 0;
+        if (list.size() == 3)
+        {
+            x = list.begin()[0]; y = list.begin()[1]; z = list.begin()[2];
+        }
+    };
+#endif
 }
 CvPoint3D64f;
 
 /** constructs CvPoint3D64f structure. */
 CV_INLINE  CvPoint3D64f  cvPoint3D64f( double x, double y, double z )
 {
-    CvPoint3D64f p;
-
-    p.x = x;
-    p.y = y;
-    p.z = z;
-
+    CvPoint3D64f p = { x, y, z };
     return p;
 }
 
@@ -1032,10 +1167,23 @@ typedef struct CvSize
     int width;
     int height;
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvSize() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvSize(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 2);
+        width = 0; height = 0;
+        if (list.size() == 2)
+        {
+            width = list.begin()[0]; height = list.begin()[1];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvSize(int w = 0, int h = 0): width(w), height(h) {}
     template<typename _Tp>
     CvSize(const cv::Size_<_Tp>& sz): width(cv::saturate_cast<int>(sz.width)), height(cv::saturate_cast<int>(sz.height)) {}
+#endif
+#ifdef __cplusplus
     template<typename _Tp>
     operator cv::Size_<_Tp>() const { return cv::Size_<_Tp>(cv::saturate_cast<_Tp>(width), cv::saturate_cast<_Tp>(height)); }
 #endif
@@ -1045,23 +1193,48 @@ CvSize;
 /** constructs CvSize structure. */
 CV_INLINE  CvSize  cvSize( int width, int height )
 {
-    CvSize s;
-
-    s.width = width;
-    s.height = height;
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvSize s = { width, height };
+#else
+    CvSize s(width, height);
+#endif
+    return s;
+}
 
+#ifdef __cplusplus
+CV_INLINE CvSize cvSize(const cv::Size& sz)
+{
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvSize s = { sz.width, sz.height };
+#else
+    CvSize s(sz.width, sz.height);
+#endif
     return s;
 }
+#endif
 
 typedef struct CvSize2D32f
 {
     float width;
     float height;
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvSize2D32f() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvSize2D32f(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 2);
+        width = 0; height = 0;
+        if (list.size() == 2)
+        {
+            width = list.begin()[0]; height = list.begin()[1];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvSize2D32f(float w = 0, float h = 0): width(w), height(h) {}
     template<typename _Tp>
     CvSize2D32f(const cv::Size_<_Tp>& sz): width(cv::saturate_cast<float>(sz.width)), height(cv::saturate_cast<float>(sz.height)) {}
+#endif
+#ifdef __cplusplus
     template<typename _Tp>
     operator cv::Size_<_Tp>() const { return cv::Size_<_Tp>(cv::saturate_cast<_Tp>(width), cv::saturate_cast<_Tp>(height)); }
 #endif
@@ -1071,13 +1244,25 @@ CvSize2D32f;
 /** constructs CvSize2D32f structure. */
 CV_INLINE  CvSize2D32f  cvSize2D32f( double width, double height )
 {
-    CvSize2D32f s;
-
-    s.width = (float)width;
-    s.height = (float)height;
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvSize2D32f s = { (float)width, (float)height };
+#else
+    CvSize2D32f s((float)width, (float)height);
+#endif
+    return s;
+}
+#ifdef __cplusplus
+template<typename _Tp>
+CvSize2D32f cvSize2D32f(const cv::Size_<_Tp>& sz)
+{
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvSize2D32f s = { (float)sz.width, (float)sz.height };
+#else
+    CvSize2D32f s((float)sz.width, (float)sz.height);
+#endif
     return s;
 }
+#endif
 
 /** @sa RotatedRect
  */
@@ -1088,15 +1273,37 @@ typedef struct CvBox2D
     float angle;          /**< Angle between the horizontal axis           */
                           /**< and the first side (i.e. length) in degrees */
 
-#ifdef __cplusplus
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvBox2D(CvPoint2D32f c = CvPoint2D32f(), CvSize2D32f s = CvSize2D32f(), float a = 0) : center(c), size(s), angle(a) {}
     CvBox2D(const cv::RotatedRect& rr) : center(rr.center), size(rr.size), angle(rr.angle) {}
+#endif
+#ifdef __cplusplus
     operator cv::RotatedRect() const { return cv::RotatedRect(center, size, angle); }
 #endif
 }
 CvBox2D;
 
 
+#ifdef __cplusplus
+CV_INLINE CvBox2D cvBox2D(CvPoint2D32f c = CvPoint2D32f(), CvSize2D32f s = CvSize2D32f(), float a = 0)
+{
+    CvBox2D self;
+    self.center = c;
+    self.size = s;
+    self.angle = a;
+    return self;
+}
+CV_INLINE CvBox2D cvBox2D(const cv::RotatedRect& rr)
+{
+    CvBox2D self;
+    self.center = cvPoint2D32f(rr.center);
+    self.size = cvSize2D32f(rr.size);
+    self.angle = rr.angle;
+    return self;
+}
+#endif
+
+
 /** Line iterator state: */
 typedef struct CvLineIterator
 {
@@ -1122,7 +1329,19 @@ typedef struct CvSlice
 {
     int  start_index, end_index;
 
-#if defined(__cplusplus) && !defined(__CUDACC__)
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvSlice() __attribute__(( warning("Non-initialized variable") )) {}
+    template<typename _Tp> CvSlice(const std::initializer_list<_Tp> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 2);
+        start_index = end_index = 0;
+        if (list.size() == 2)
+        {
+            start_index = list.begin()[0]; end_index = list.begin()[1];
+        }
+    };
+#endif
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus) && !defined(__CUDACC__)
     CvSlice(int start = 0, int end = 0) : start_index(start), end_index(end) {}
     CvSlice(const cv::Range& r) { *this = (r.start != INT_MIN && r.end != INT_MAX) ? CvSlice(r.start, r.end) : CvSlice(0, CV_WHOLE_SEQ_END_INDEX); }
     operator cv::Range() const { return (start_index == 0 && end_index == CV_WHOLE_SEQ_END_INDEX ) ? cv::Range::all() : cv::Range(start_index, end_index); }
@@ -1132,13 +1351,21 @@ CvSlice;
 
 CV_INLINE  CvSlice  cvSlice( int start, int end )
 {
-    CvSlice slice;
-    slice.start_index = start;
-    slice.end_index = end;
-
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvSlice slice = { start, end };
+#else
+    CvSlice slice(start, end);
+#endif
     return slice;
 }
 
+#if defined(__cplusplus)
+CV_INLINE  CvSlice  cvSlice(const cv::Range& r)
+{
+    CvSlice slice = (r.start != INT_MIN && r.end != INT_MAX) ? cvSlice(r.start, r.end) : cvSlice(0, CV_WHOLE_SEQ_END_INDEX);
+    return slice;
+}
+#endif
 
 
 /************************************* CvScalar *****************************************/
@@ -1148,13 +1375,22 @@ typedef struct CvScalar
 {
     double val[4];
 
-#ifdef __cplusplus
+#ifdef CV__VALIDATE_UNUNITIALIZED_VARS
+    CvScalar() __attribute__(( warning("Non-initialized variable") )) {}
+    CvScalar(const std::initializer_list<double> list)
+    {
+        CV_Assert(list.size() == 0 || list.size() == 4);
+        val[0] = val[1] = val[2] = val[3] = 0;
+        if (list.size() == 4)
+        {
+            val[0] = list.begin()[0]; val[1] = list.begin()[1]; val[2] = list.begin()[2]; val[3] = list.begin()[3];
+        }
+    };
+#elif defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvScalar() {}
     CvScalar(double d0, double d1 = 0, double d2 = 0, double d3 = 0) { val[0] = d0; val[1] = d1; val[2] = d2; val[3] = d3; }
     template<typename _Tp>
     CvScalar(const cv::Scalar_<_Tp>& s) { val[0] = s.val[0]; val[1] = s.val[1]; val[2] = s.val[2]; val[3] = s.val[3]; }
-    template<typename _Tp>
-    operator cv::Scalar_<_Tp>() const { return cv::Scalar_<_Tp>(cv::saturate_cast<_Tp>(val[0]), cv::saturate_cast<_Tp>(val[1]), cv::saturate_cast<_Tp>(val[2]), cv::saturate_cast<_Tp>(val[3])); }
     template<typename _Tp, int cn>
     CvScalar(const cv::Vec<_Tp, cn>& v)
     {
@@ -1163,22 +1399,59 @@ typedef struct CvScalar
         for( ; i < 4; i++ ) val[i] = 0;
     }
 #endif
+#ifdef __cplusplus
+    template<typename _Tp>
+    operator cv::Scalar_<_Tp>() const { return cv::Scalar_<_Tp>(cv::saturate_cast<_Tp>(val[0]), cv::saturate_cast<_Tp>(val[1]), cv::saturate_cast<_Tp>(val[2]), cv::saturate_cast<_Tp>(val[3])); }
+#endif
 }
 CvScalar;
 
 CV_INLINE  CvScalar  cvScalar( double val0, double val1 CV_DEFAULT(0),
                                double val2 CV_DEFAULT(0), double val3 CV_DEFAULT(0))
 {
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvScalar scalar = CV_STRUCT_INITIALIZER;
+#else
     CvScalar scalar;
+#endif
     scalar.val[0] = val0; scalar.val[1] = val1;
     scalar.val[2] = val2; scalar.val[3] = val3;
     return scalar;
 }
 
+#ifdef __cplusplus
+CV_INLINE CvScalar cvScalar()
+{
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvScalar scalar = CV_STRUCT_INITIALIZER;
+#else
+    CvScalar scalar;
+#endif
+    scalar.val[0] = scalar.val[1] = scalar.val[2] = scalar.val[3] = 0;
+    return scalar;
+}
+CV_INLINE CvScalar cvScalar(const cv::Scalar& s)
+{
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvScalar scalar = CV_STRUCT_INITIALIZER;
+#else
+    CvScalar scalar;
+#endif
+    scalar.val[0] = s.val[0];
+    scalar.val[1] = s.val[1];
+    scalar.val[2] = s.val[2];
+    scalar.val[3] = s.val[3];
+    return scalar;
+}
+#endif
 
 CV_INLINE  CvScalar  cvRealScalar( double val0 )
 {
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvScalar scalar = CV_STRUCT_INITIALIZER;
+#else
     CvScalar scalar;
+#endif
     scalar.val[0] = val0;
     scalar.val[1] = scalar.val[2] = scalar.val[3] = 0;
     return scalar;
@@ -1186,7 +1459,11 @@ CV_INLINE  CvScalar  cvRealScalar( double val0 )
 
 CV_INLINE  CvScalar  cvScalarAll( double val0123 )
 {
+#if !(defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus))
+    CvScalar scalar = CV_STRUCT_INITIALIZER;
+#else
     CvScalar scalar;
+#endif
     scalar.val[0] = val0123;
     scalar.val[1] = val0123;
     scalar.val[2] = val0123;

modules/core/src/matrix_c.cpp

@@ -4,20 +4,24 @@
 
 // glue
 
-CvMatND::CvMatND(const cv::Mat& m)
+CvMatND cvMatND(const cv::Mat& m)
 {
-    cvInitMatNDHeader(this, m.dims, m.size, m.type(), m.data );
+    CvMatND self;
+    cvInitMatNDHeader(&self, m.dims, m.size, m.type(), m.data );
     int i, d = m.dims;
     for( i = 0; i < d; i++ )
-        dim[i].step = (int)m.step[i];
-    type |= m.flags & cv::Mat::CONTINUOUS_FLAG;
+        self.dim[i].step = (int)m.step[i];
+    self.type |= m.flags & cv::Mat::CONTINUOUS_FLAG;
+    return self;
 }
 
-_IplImage::_IplImage(const cv::Mat& m)
+_IplImage cvIplImage(const cv::Mat& m)
 {
+    _IplImage self;
     CV_Assert( m.dims <= 2 );
-    cvInitImageHeader(this, m.size(), cvIplDepth(m.flags), m.channels());
-    cvSetData(this, m.data, (int)m.step[0]);
+    cvInitImageHeader(&self, cvSize(m.size()), cvIplDepth(m.flags), m.channels());
+    cvSetData(&self, m.data, (int)m.step[0]);
+    return self;
 }
 
 namespace cv {

modules/imgproc/include/opencv2/imgproc/types_c.h

@@ -410,7 +410,7 @@ typedef struct CvMoments
     double  mu20, mu11, mu02, mu30, mu21, mu12, mu03; /**< central moments */
     double  inv_sqrt_m00; /**< m00 != 0 ? 1/sqrt(m00) : 0 */
 
-#ifdef __cplusplus
+#if defined(CV__ENABLE_C_API_CTORS) && defined(__cplusplus)
     CvMoments(){}
     CvMoments(const cv::Moments& m)
     {
@@ -430,6 +430,36 @@ typedef struct CvMoments
 }
 CvMoments;
 
+#ifdef __cplusplus
+} // extern "C"
+
+CV_INLINE CvMoments cvMoments()
+{
+#if !defined(CV__ENABLE_C_API_CTORS)
+    CvMoments self = CV_STRUCT_INITIALIZER; return self;
+#else
+    return CvMoments();
+#endif
+}
+
+CV_INLINE CvMoments cvMoments(const cv::Moments& m)
+{
+#if !defined(CV__ENABLE_C_API_CTORS)
+    double am00 = std::abs(m.m00);
+    CvMoments self = {
+        m.m00, m.m10, m.m01, m.m20, m.m11, m.m02, m.m30, m.m21, m.m12, m.m03,
+        m.mu20, m.mu11, m.mu02, m.mu30, m.mu21, m.mu12, m.mu03,
+        am00 > DBL_EPSILON ? 1./std::sqrt(am00) : 0
+    };
+    return self;
+#else
+    return CvMoments(m);
+#endif
+}
+
+extern "C" {
+#endif // __cplusplus
+
 /** Hu invariants */
 typedef struct CvHuMoments
 {