add visibility macros (ros2#28)

rosbag2_storage_default_plugins/include/rosbag2_storage_default_plugins/visibility_control.hpp

@@ -0,0 +1,58 @@
+// Copyright 2018 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ROSBAG2_STORAGE_DEFAULT_PLUGINS__VISIBILITY_CONTROL_HPP_
+#define ROSBAG2_STORAGE_DEFAULT_PLUGINS__VISIBILITY_CONTROL_HPP_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+// This logic was borrowed (then namespaced) from the examples on the gcc wiki:
+//     https://gcc.gnu.org/wiki/Visibility
+
+#if defined _WIN32 || defined __CYGWIN__
+  #ifdef __GNUC__
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_EXPORT __attribute__ ((dllexport))
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_IMPORT __attribute__ ((dllimport))
+  #else
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_EXPORT __declspec(dllexport)
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_IMPORT __declspec(dllimport)
+  #endif
+  #ifdef ROSBAG2_STORAGE_DEFAULT_PLUGINS_BUILDING_DLL
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC ROSBAG2_STORAGE_DEFAULT_PLUGINS_EXPORT
+  #else
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC ROSBAG2_STORAGE_DEFAULT_PLUGINS_IMPORT
+  #endif
+  #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC_TYPE ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC
+  #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_LOCAL
+#else
+  #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_EXPORT __attribute__ ((visibility("default")))
+  #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_IMPORT
+  #if __GNUC__ >= 4
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC __attribute__ ((visibility("default")))
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_LOCAL  __attribute__ ((visibility("hidden")))
+  #else
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC
+    #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_LOCAL
+  #endif
+  #define ROSBAG2_STORAGE_DEFAULT_PLUGINS_PUBLIC_TYPE
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // ROSBAG2_STORAGE_DEFAULT_PLUGINS__VISIBILITY_CONTROL_HPP_