+#if (__GNUC__ >= 4)
+#ifdef SD_EXPORT_SYMBOLS
+/* Export symbols */
+#define _sd_export_ __attribute__ ((visibility("default")))
+#else
+/* Don't export the symbols */
+#define _sd_export_ __attribute__ ((visibility("hidden")))
+#endif
+#else
+#define _sd_export_
+#endif
+