diff --git a/src/eastasianwidthdef.h b/src/eastasianwidthdef.h
index ba89040..0f82d37 100644
--- a/src/eastasianwidthdef.h
+++ b/src/eastasianwidthdef.h
@@ -26,6 +26,10 @@
 
 #include "unibreakdef.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * East Asian Width (ea) class.  This is defined in Unicode Standard
  * Annex 11.
@@ -64,4 +68,8 @@ enum EastAsianWidthClass ub_get_char_eaw_class(utf32_t ch);
 */
 bool ub_is_op_east_asian(utf32_t ch);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* EASTASIANWIDTHDEF_H */