diff --git a/uisimulator/win32/sprintf.h b/uisimulator/win32/sprintf.h
index 5624871ba6..5bfc6c1d86 100644
--- a/uisimulator/win32/sprintf.h
+++ b/uisimulator/win32/sprintf.h
@@ -22,6 +22,7 @@
 
 #include <stddef.h>
 #include <stdarg.h>
+#include <stdio.h>
 
 int snprintf (char *buf, size_t size, const char *fmt, ...);
 #ifndef NOCYGWIN