Re: General clipboard issue on cygwin (mintty, putclip, getclip, /dev/clipboard)

On Mon, 23 Feb 2026 23:04:31 -0700
Brian Inglis wrote:
> On 2026-02-23 18:36, Takashi Yano via Cygwin wrote:
> > I encountered a clipboard issue common to cygwin.
> > 
> > Affected components:
> > /dev/clipboard, putclip/getclip, mintty
> > 
> > The issue:
> > If the clipbard is opened by `OpenClipboard(NULL)`, occasionally
> > SetClipboardData() and GetClipboardData() fails with
> > ERROR_CLIPBOARD_NOT_OPEN.
> > 
> > When UltraVNC Viewer (https://uvnc.com/) is opened, this issue
> > happens with a very high probability (> ~90%).
> > 
> > $ echo AAAA > /dev/clipboard
> > echo: write error: Permission denied
> > 
> > On mintty, text selection by mouse and clicking center button
> > fails at the first attempt.
> > 
> > For putlclip/getclip, the following command outputs nothing
> > in a few attempts. ("ABCD" is lost.)
> > $ echo ABCD |putclip; for a in `seq 100`; do getclip |putclip; done; getclip
> 
> Hi,
> 
> Your patch attachment is typed as:
> 
> 	Content-Type: plain/text;
> 
> rather than the standard mime type text/plain;
> please check your /etc/mime.types, ~/.sylpheed/mime.types, ~/.*/mime.types, or 
> other alternatives for that incorrect mime type mapping, replace with the 
> standard, and resend with the attachment, so we can read it inline, without 
> saving or other operations to decode it.

Thanks!

Actually, my MUA (sylpheed) uses "application/octet-stream" for .patch file,
so I manually changed it to "text/plain". But accsidendly, it was "plain/text"
by my mistake.

I resend it on this mail.

-- 
Takashi Yano <[email protected]>


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From 1e1f3aca99a9309c7521980d364c32cba02f038e Mon Sep 17 00:00:00 2001
From: Takashi Yano <[email protected]>
Date: Thu, 19 Feb 2026 16:04:15 +0900
Subject: [PATCH] Cygwin: clipboard: Add workaround for
 ERROR_CLIPBOARD_NOT_OPEN

---
 winsup/cygwin/fhandler/clipboard.cc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler/clipboard.cc b/winsup/cygwin/fhandler/clipboard.cc
index 12691c7c1..221aaac62 100644
--- a/winsup/cygwin/fhandler/clipboard.cc
+++ b/winsup/cygwin/fhandler/clipboard.cc
@@ -26,10 +26,16 @@ static inline bool
 open_clipboard ()
 {
   const int max_retry = 10;
+retry:
   for (int i = 0; i < max_retry; i++)
     {
       if (OpenClipboard (NULL))
-	return true;
+	{
+	  if (!GetClipboardData (CF_UNICODETEXT)
+	      && GetLastError () == ERROR_CLIPBOARD_NOT_OPEN)
+	    goto retry;
+	  return true;
+	}
       Sleep (1);
     }
   return false;
-- 
2.51.0