Ctrl+C not working with windows programs in Cygwin 1.7.16

Roger K. Wells ROGER.K.WELLS@saic.com
Thu Aug 2 21:22:00 GMT 2012

On 08/02/2012 04:26 PM, Daniel Colascione wrote:
> On 8/2/2012 12:32 PM, Marcin Kielar wrote:
>> Steps to reproduce:
>> 1. Start cygwin using cygwin.bat
>> 2. Run `ping -t google.com`
>> 3. Try breaking it with Ctrl+C
> This problem arises from Cygwin's use of CREATE_NEW_PROCESS_GROUP. From MSDN:
> "When a process is created with CREATE_NEW_PROCESS_GROUP specified, an implicit
> call to SetConsoleCtrlHandler(NULL,TRUE) is made on behalf of the new process;
> this means that the new process has CTRL+C disabled. This lets shells handle
> CTRL+C themselves, and selectively pass that signal on to sub-processes.
> CTRL+BREAK is not disabled, and may be used to interrupt the process/process group."
> SetConsoleCtrlHandler(NULL,TRUE) tells a process and all its children to ignore
> control-C. This problem only affects programs run in a console --- in a pty,
> Cygwin just terminates Windows processes in response to SIGINT.
This may be true but it is a recent development.
 From the similar thread that specifies a java process my remarks:

> This is still a problem.
> CYGWIN_NT-6.1 rwells-w7 1.7.16(0.262/5/3) 2012-07-20 22:55 i686 Cygwin
> We have been developing CLI applications for close to 20 years and 
> have never had a
> problem with the cygwin bash shell failing to pass Ctrl-C signals to 
> the application until now.
> Luckily the cmd.exe still does.
> Let me know if it something that I can help track down.  Glad to help 
> if possible.

Roger Wells, P.E.
221 Third St
Newport, RI 02840
401-847-4210 (voice)
401-849-1585 (fax)

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