diff --git a/file.c b/file.c
index b035a0b064..15979c4f55 100644
--- a/file.c
+++ b/file.c
@@ -2605,6 +2605,9 @@ rb_home_dir(const char *user, VALUE result)
 {
     const char *dir;
     char *buf;
+#if defined DOSISH || defined __CYGWIN__
+    char *p;
+#endif
     long dirlen;
 
     if (!user || !*user) {