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Date: Thu, 02 Aug 2012 13:26:02 -0700
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To: cygwin AT cygwin DOT com
Subject: Re: Ctrl+C not working with windows programs in Cygwin 1.7.16
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On 8/2/2012 12:32 PM, Marcin Kielar wrote:
> Steps to reproduce:
>=20
> 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 MSD=
N:

"When a process is created with CREATE_NEW_PROCESS_GROUP specified, an impl=
icit
call to SetConsoleCtrlHandler(NULL,TRUE) is made on behalf of the new proce=
ss;
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/proces=
s group."

SetConsoleCtrlHandler(NULL,TRUE) tells a process and all its children to ig=
nore
control-C. This problem only affects programs run in a console --- in a pty,
Cygwin just terminates Windows processes in response to SIGINT.


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