[PATCH] Cygwin: Make native clipboard layout same for 32- and 64-bit

Mark Geisert mark@maxrnd.com
Mon Oct 11 06:13:41 GMT 2021

Ken Brown wrote:
> On 10/9/2021 10:29 AM, Jon Turney wrote:
>>> On 10/8/2021 5:52 AM, Takashi Yano wrote:

Thanks all for the comments; much appreciated.  They'll be factored into v2 in one 
form or another.  I pronounced my original patch "bad" not because of any problem 
with code operation or struct cygcb_t definition.  I used anonymous union and 
anonymous struct internally to mostly realize what Takashi suggested for layout, 
just naming the items cb_* rather than tv_* or other.  The code works as intended, 
32- and 64-bit.

It's just that after submitting the patch I realized that, if we really are going 
to support both Cygwin archs (x86_64 and i686), there is still the issue of 
different cygcb_t layouts between Cygwin versions being ignored.

Specifically, the fhandler_clipboard::fstat routine can't tell which Cygwin 
environment has set the clipboard contents.  My original patch takes care of 
32-bit and 64-bit, providing both are running Cygwin >= 3.3.0 (presumably).  What 
if it was a different version (pre 3.3.0) that set the contents?

So I'm working on a heuristic to identify which cygcb_t layout is present in the 
clipboard data.  This will hopefully distinguish between the 3 historical cygcb_t 
layouts as well as x86_64 differing from i686 for each one.
Stay tuned,


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