Index: uspace/lib/c/include/errno.h
===================================================================
--- uspace/lib/c/include/errno.h	(revision 4805495a910f793f8918c13f029a38a5bb548154)
+++ uspace/lib/c/include/errno.h	(revision 00e8290f885b3dc03a5c5a191983eb336d1e852c)
@@ -38,8 +38,17 @@
 #include <_bits/errno.h>
 #include <abi/errno.h>
+#include <_bits/decls.h>
 
-#define errno  (*(__errno()))
+__HELENOS_DECLS_BEGIN;
 
 extern errno_t *__errno(void) __attribute__((const));
+
+__HELENOS_DECLS_END;
+
+#ifdef __cplusplus
+#define errno  (*(::helenos::__errno()))
+#else
+#define errno  (*(__errno()))
+#endif
 
 #endif