diff --git a/Source/kwsys/kwsys_ios_iosfwd.h.in b/Source/kwsys/kwsys_ios_iosfwd.h.in
index ec0a939a8..d94d51a70 100644
--- a/Source/kwsys/kwsys_ios_iosfwd.h.in
+++ b/Source/kwsys/kwsys_ios_iosfwd.h.in
@@ -23,6 +23,7 @@
 
 #if @KWSYS_NAMESPACE@_IOS_HAVE_ANSI
 # include <iosfwd>
+# include <fstream>
 #else
 class fstream;
 class ifstream;