diff --git a/fcgi/libfcgi/fcgio.cpp b/fcgi/libfcgi/fcgio.cpp
index 95e28ca..c93e46d 100644
--- a/fcgi/libfcgi/fcgio.cpp
+++ b/fcgi/libfcgi/fcgio.cpp
@@ -24,6 +24,7 @@
 
 #include <limits.h>
 #include "fcgio.h"
+#include <cstdio>
 
 using std::streambuf;
 using std::istream;