Emacs can't capture fzf output in Windows 10

[Shuguang Sun]

Dear all,


I'm trying to use fzf (junegunn/fzf) in windows, however it seems emacs can't 
capture the output of fzf.


Example:  fzf with -filter will be in filter mode and do not start 
interactive finder. 

- In shell (cmd): "fzf.exe --filter=tmp" will not exit
- In shell (cmd): "fzf.exe --filter=tmp > aa.txt"  will not exit

- (call-process "cmd.exe" nil t nil "/C" "start" "fzf" "--filter=tmp") will 
give a flash window (with list of findings) and print 0 in emacs.

- (shell-command "fzf --filter=tmp") will lead to a message (Shell command 
failed with code 1 and no output)
- (shell-command-to-string "fzf --filter=tmp") give a empty string


However if I run "fzf --filter=tmp" in the CMD box it will provide a list of 
finding, and "fzf --filter=tmp > aa.txt" will print the findings to file 
aa.txt.


It can't run fzf in interactive mode as I understand there is no true term for 
emacs in windows but why it can't be run in filter mode?





It is not put in the bugs report as I don't understand the mechanism whether it 
is a bug.



- Windows 10
- Emacs 28 (I think is not only for 28)



System information:
In GNU Emacs 28.0.50 (build 2, x86_64-w64-mingw32)  of 2020-02-27
Repository revision: 07da629926daf849aab248175c88cf53a5e21558
Repository branch: master
Windowing system distributor 'Microsoft Corp.', version 10.0.18362
System Description: Microsoft Windows 10 Enterprise (v10.0.1903.18362.657)




Thanks,
Shuguang Sun