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Old 08-05-2014, 01:06 AM   #1
bsr_linux
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Sigaction shows varied signals when checked at parent process after the child exits


Parent process forked a child to print() some output using fflush(NULL) and does _exit(0);

After the child exits, the parent where I had added a sigaction for signals 1-15 and 33-300 shows varied signal number each time, the child is forked, prints and exits. sometimes it shows 11, 43 , 100, 123 ....


How to figure out why such bogus values are coming? If I add explicitly a handler for SIGCHLD, it works fine!! If no user-defined handler, some bogus signal no is shown each time ...

Any pointers or help in this regard is appreciated.

Thanks,
bsr
 
Old 08-05-2014, 06:53 AM   #2
pan64
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looks like you got a random number from the outer space, not a real signal...
 
Old 08-05-2014, 07:08 AM   #3
bsr_linux
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But what is the reason for such signals, which are not standard/real-time? Can I use sigaction to catch and process such signals that is > 64 ?
 
Old 08-05-2014, 07:53 AM   #4
pan64
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You did not catch those signals, you got a random number instead of the real signal number.
 
Old 08-05-2014, 08:04 AM   #5
bsr_linux
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I used sigaction to register for all signals ranging from 1 to 16 and 18 to 300.
But it is not invoking the handler for any signal in this range.

If I include signal 17 (SIGCHLD), I can see that the handler in sigaction is invoked!
 
Old 08-05-2014, 08:09 AM   #6
pan64
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for me sigaction dies for 9, 19, 32, 33 and every other signal above 64. would be nice to see your code....
 
  


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