Re: dup2 mingw failure

[Simon Josefsson]

Eric Blake <address@hidden> writes:

> According to Simon Josefsson on 1/8/2010 2:36 AM:
>> I got this on MinGW:
>> 
>> test-dup2.c:140: assertion failed
>> FAIL: test-dup2.exe
>
> I wish mingw had a better version number reporting scheme.  I can't
> reproduce the failure when I cross-compile from cygwin to mingw, then run
> the program natively on Windows (that is, using the mingw libraries that
> ship with cygwin 1.7.1), but I'll take your word for it.  Maybe this is a
> bug in wine?

Yes it was:

http://bugs.winehq.org/show_bug.cgi?id=21289

The problem is that Wine's dup2 will return 0 for negative desired_fd,
and gnulib's rpl_dup2 will then make the return value for rpl_dup2 be
desired_fd.  Which is wrong.  I pushed the improved comment below.

/Simon

>From 581419c98c50af5daefcbb07ca1cbc16539db072 Mon Sep 17 00:00:00 2001
From: Simon Josefsson <address@hidden>
Date: Fri, 8 Jan 2010 23:29:17 +0100
Subject: [PATCH] lib/dup2.c (rpl_dup2): Improve comment.

---
 ChangeLog  |    4 ++++
 lib/dup2.c |    4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b1d9a6a..4d4137e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-01-08  Simon Josefsson  <address@hidden>
+
+       * lib/dup2.c (rpl_dup2): Improve comment.
+
 2010-01-08  Eric Blake  <address@hidden>
 
        maint.mk: allow packages to add makefile @@ exceptions
diff --git a/lib/dup2.c b/lib/dup2.c
index 9b6a8f6..a4422bf 100644
--- a/lib/dup2.c
+++ b/lib/dup2.c
@@ -52,8 +52,8 @@ rpl_dup2 (int fd, int desired_fd)
         }
       return fd;
     }
-  /* Some mingw versions also return the wrong value if desired_fd is
-     negative but not -1.  */
+  /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
+     http://bugs.winehq.org/show_bug.cgi?id=21289 */
   if (desired_fd < 0)
     {
       errno = EBADF;
-- 
1.6.6