diff --git a/include/mrbconf.h b/include/mrbconf.h
index cf8217b23..b0a33aa43 100644
--- a/include/mrbconf.h
+++ b/include/mrbconf.h
@@ -7,6 +7,9 @@
 #ifndef MRUBYCONF_H
 #define MRUBYCONF_H
 
+#if defined(__cplusplus)
+#define __STDC_LIMIT_MACROS
+#endif
 #include <stdint.h>
 
 /* configuration options: */