diff --git a/kwsys_ios_iosfwd.h.in b/kwsys_ios_iosfwd.h.in
index 3c3700590e650f34cc85f70f901182af3fd016fb..c830c12d925e03ee90dab1626df758a3cbfa9ce0 100644
--- a/kwsys_ios_iosfwd.h.in
+++ b/kwsys_ios_iosfwd.h.in
@@ -23,6 +23,7 @@
 
 #if @KWSYS_NAMESPACE@_IOS_HAVE_ANSI
 # include <iosfwd>
+# include <fstream>
 #else
 class fstream;
 class ifstream;