diff --git a/wcwidth.h b/wcwidth.h
index 1c55ba4..38c17ac 100644
--- a/wcwidth.h
+++ b/wcwidth.h
@@ -3,6 +3,10 @@
 
 #include <stdlib.h>
 
+__BEGIN_DECLS
+
 int wcwidth(wchar_t ucs);
 
+__END_DECLS
+
 #endif