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Date: Sat, 19 May 2001 10:57:13 -0400
From: Christopher Faylor <cgf AT redhat DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: spawnl and signals
Message-ID: <20010519105713.A7329@redhat.com>
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References: <200105191450 DOT PAA05445 AT malus DOT maths DOT soton DOT ac DOT uk>
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In-Reply-To: <200105191450.PAA05445@malus.maths.soton.ac.uk>; from J.L.Moxham@maths.soton.ac.uk on Sat, May 19, 2001 at 03:50:37PM +0100

On Sat, May 19, 2001 at 03:50:37PM +0100, Jason Moxham wrote:
>
>If you compile and run program below with latest cygwin you get the
>expected behavour
>
>// This is jay.exe
>
>#include <stdio.h>
>#include <stdlib.h>
>#include <signal.h>
>
>volatile int gotsignal=0;
>
>void	sighandler(int signum){gotsignal=signum;return;}
>
>int	main(void)
>{int a;
>
>printf("in jay.exe\n");fflush(0);
>signal(SIGINT,sighandler);
>do{
>if(gotsignal!=0)
>  {printf("got signal %d\n",gotsignal);
>   fflush(0);
>   gotsignal=0;break;}
>}while(1);
>return 0;}
>
>However if you compile and run the program below which calls the above
>program then the ctrl-C signal is never detected
>
>// this is jay1.exe
>
>#include <stdio.h>
>#include <stdlib.h>
>#include <signal.h>
>#include <process.h>
>
>volatile int gotsignal=0;
>
>void	sighandler(int signum){gotsignal=signum;return;}
>
>int	main(void)
>{int a;
>
>spawnl(_P_NOWAIT,"./jay.exe","./jay.exe",0);
>//execl("./jay.exe","./jay.exe",0);
>
>return 0;}
>
>this is running under Window 98SE under a DOS prompt
>changing the spawnl to a execl makes it work as it should

P_NOWAIT starts a background process.  Background processes don't
respond to CTRL-Cs.  It is the same as if you typed "jay.exe&" in bash.
If you send a specific SIGINT to the process it should stop though.

cgf

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