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Old 02-03-2004, 01:40 AM   #1
skywalker27182
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Registered: Nov 2003
Posts: 35

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Possible to lock out interrupts forever?


hi,
someone please tell me what the following code does:

Code:
main()
{

     signal(SIGINT, sigcatcher);
     for( ; ; ) printf("1");
}

sigcatcher()
{
     signal(SIGINT, sigcatcher);
     for( ; ; ) printf("2");
}

Last edited by skywalker27182; 02-03-2004 at 01:41 AM.
 
Old 02-03-2004, 02:41 AM   #2
rmartine
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Registered: Dec 2002
Location: San Luis Obispo, CA
Distribution: Fedora Core 3
Posts: 618

Rep: Reputation: 30
What it looks like you're doing is making your own signal handler for SIGINT. Instead of Linux doing what it nomally does when SIGINT is thrown, your program will run sigcather() instead. Instead of restting the signal it looks like you're telling Linux to continue using sigcather() as the handler.

Hope that helps.
 
Old 02-04-2004, 01:20 AM   #3
skywalker27182
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Registered: Nov 2003
Posts: 35

Original Poster
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what i was thinking was whenever an interrupt comes, the kernel will pass on to another infinite loop(in sigcatcher) and if there is one more interrupt, it will go back to the first infinite loop(in main) and so on. also, i found out that SIGINT is the keyboard interrupt, so in place of SIGINT if i place a signal that kernel sends the process, SIGTERM, is it possible to lock the interrupts out?
 
Old 02-04-2004, 08:12 AM   #4
jerrymei
LQ Newbie
 
Registered: Feb 2004
Distribution: Red Hat
Posts: 20

Rep: Reputation: 0
Hi,

Well it seems that you are using the signals in an unreliable manner. I suggest if you want to deal with signals take a look at the following functions wich are called reliable signal functions:

sigemptyset(sigset_t, *set);
sigaddset(*set,signo);
sigdelset(*set,signo);
sigismember(*set,signo);

struct sigaction{
void (*sa_handler);
sigset_t sa_mask;
int sa_flags;
}

int sigaction(int signum,struct sigaction *act,struct sigaction *oldact);
int sigprocmask(int how,sigset_t *set,sigset_t *oldset);
int sigpendign(sigset_t *set);
int sigsuspend(sigset_t *set);


Hope it would help.
 
  


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