Incompatible clipboard format between 32bit and 64bit cygwin

Thomas Wolff
Sun Sep 26 18:41:29 GMT 2021

Am 26.09.2021 um 20:37 schrieb Thomas Wolff:
> Am 26.09.2021 um 11:50 schrieb Mark Geisert:
>> Hi Takashi,
>> Takashi Yano via Cygwin wrote:
>>> I noticed that cygwin clipboard is not compatible
>>> between 32bit and 64bit cygwin.
>>> If I run 'echo AAAAAAAA > /dev/clipboard' in 32bit cygwin,
>>> and run 'cat /dev/clipboard' in 64bit cygwin, this result in
>>> cat: /dev/clipboard: Bad address
>>> This is because the structure
>>> typedef struct
>>> {
>>>    timestruc_t   timestamp;
>>>    size_t    len;
>>>    char      data[1];
>>> } cygcb_t;
>>> defined in has different size.
>>> Is this the known issue?
>> I doubt anybody has ever tried what you did. 
> I have and it failed; I just didn't find it important enough to report 
> it here... Thanks for the plan to fix it.
>> I have been testing getclip and putclip between 32- and 64-bit 
>> environments, but neglected to test Cygwin-internal clipboard format 
>> that prepends cygcb_t to the user-supplied data. 
As we're at it, what's the purpose of a cygwin-internal clipboard format 
at all?
Copy/paste between 32bit/64bit mintty works; mintty uses Windows 
CF_UNICODETEXT clipboard format.

>> So getclip and putclip will need fixing as well.
>> I will submit a Cygwin patch to fix /dev/clipboard usage and a 
>> similar patch to cygutils for the utilities.
>> I appreciate your help in uncovering and investigating bugs in 
>> clipboard support.
>> Thanks & Regards,
>> ..mark

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