diff --git a/include/string b/include/string
index 6b11e02..15713f0 100644
--- a/include/string
+++ b/include/string
@@ -358,6 +358,7 @@
 #include <__config>
 #include <iosfwd>
 #include <cstring>
+#include <cstdio>  // For EOF.
 #include <cwchar>
 #include <algorithm>
 #include <iterator>