* file.c (rb_file_s_rename): use errno if set properly.

  fixed: [ruby-dev:29293]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@10747 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 1 deletions

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__)