Merge pull request #14717 from alalek:core_visibility_handling

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

@@ -371,10 +371,10 @@ Cv64suf;
 #  define OPENCV_DISABLE_DEPRECATED_COMPATIBILITY
 #endif
 
-#ifdef CVAPI_EXPORTS
-# if (defined _WIN32 || defined WINCE || defined __CYGWIN__)
+#ifndef CV_EXPORTS
+# if (defined _WIN32 || defined WINCE || defined __CYGWIN__) && defined(CVAPI_EXPORTS)
 #   define CV_EXPORTS __declspec(dllexport)
-# elif defined __GNUC__ && __GNUC__ >= 4
+# elif defined __GNUC__ && __GNUC__ >= 4 && (defined(CVAPI_EXPORTS) || defined(__APPLE__))
 #   define CV_EXPORTS __attribute__ ((visibility ("default")))
 # endif
 #endif

modules/python/common.cmake

@@ -61,7 +61,6 @@ ocv_update(OPENCV_PYTHON_EXTENSION_BUILD_PATH "${LIBRARY_OUTPUT_PATH}/${MODULE_I
 set_target_properties(${the_module} PROPERTIES
                       LIBRARY_OUTPUT_DIRECTORY  "${OPENCV_PYTHON_EXTENSION_BUILD_PATH}"
                       ARCHIVE_OUTPUT_NAME ${the_module}  # prevent name conflict for python2/3 outputs
-                      DEFINE_SYMBOL CVAPI_EXPORTS
                       PREFIX ""
                       OUTPUT_NAME cv2
                       SUFFIX ${CVPY_SUFFIX})

modules/python/src2/cv2.cpp

@@ -1769,8 +1769,12 @@ static int to_ok(PyTypeObject *to)
 }
 
 
+#if defined(__GNUC__)
+#pragma GCC visibility push(default)
+#endif
+
 #if PY_MAJOR_VERSION >= 3
-extern "C" CV_EXPORTS PyObject* PyInit_cv2();
+PyMODINIT_FUNC PyInit_cv2();
 static struct PyModuleDef cv2_moduledef =
 {
     PyModuleDef_HEAD_INIT,
@@ -1783,7 +1787,7 @@ static struct PyModuleDef cv2_moduledef =
 
 PyObject* PyInit_cv2()
 #else
-extern "C" CV_EXPORTS void initcv2();
+PyMODINIT_FUNC initcv2();
 
 void initcv2()
 #endif