diff --git a/ChangeLog b/ChangeLog
index 9139d82967..d77c8852e1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Aug 19 11:28:08 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* file.c (rb_file_s_rename): use errno if set properly.
+	  fixed: [ruby-dev:29293]
+
 Fri Aug 18 01:05:57 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* lib/cgi.rb (CGI::out): specify -m0 to disable MIME decode.  a
diff --git a/file.c b/file.c
index f1527a0407..00bc40cd7f 100644
--- a/file.c
+++ b/file.c
@@ -2180,10 +2180,16 @@ rb_file_s_rename(VALUE klass, VALUE from, VALUE to)
     FilePathValue(to);
     src = StringValueCStr(from);
     dst = StringValueCStr(to);
+#if defined __CYGWIN__
+    errno = 0;
+#endif
     if (rename(src, dst) < 0) {
 #if defined __CYGWIN__
 	extern unsigned long __attribute__((stdcall)) GetLastError(void);
-	errno = GetLastError(); /* This is a Cygwin bug */
+	if (errno == 0) {	/* This is a bug of old Cygwin */
+	    /* incorrect as cygwin errno, but the last resort */
+	    errno = GetLastError();
+	}
 #elif defined DOSISH && !defined _WIN32
 	if (errno == EEXIST
 #if defined (__EMX__)