win32.c: fix dup2 return value

* win32/win32.c (rb_w32_dup2): should return the new fd on
  success, while msvcrt returns 0 wrongly.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51841 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 1 deletions

diff --git a/win32/win32.c b/win32/win32.c
index 11292a16cc..32e77c01e4 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -5934,8 +5934,9 @@ rb_w32_dup2(int oldfd, int newfd)
 
     if (oldfd == newfd) return newfd;
     ret = dup2(oldfd, newfd);
+    if (ret < 0) return ret;
     set_new_std_fd(newfd);
-    return ret;
+    return newfd;
 }
 
 /* License: Ruby's */