Problem with signal handlers

Posted by Hristo on Stack Overflow See other posts from Stack Overflow or by Hristo
Published on 2010-04-08T02:10:19Z Indexed on 2010/04/08 2:33 UTC
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how can something print 3 times when it only goes the printing code twice? I'm coding in C and the code is in a SIGCHLD signal handler I created.

void chld_signalHandler() {
 int pidadf = (int) getpid();
 printf("pidafdfaddf: %d\n", pidadf);

 while (1) {
  int termChildPID = waitpid(-1, NULL, WNOHANG);

  if (termChildPID == 0 || termChildPID == -1) {
   break;
  }

  dll_node_t *temp = head;
  while (temp != NULL) {
   printf("stuff\n");
   if (temp->pid == termChildPID && temp->type == WORK) {
    printf("inside if\n");

    // read memory mapped file b/w WORKER and MAIN
    // get statistics and write results to pipe
    char resultString[256];

    // printing TIME
    int i;
    for (i = 0; i < 24; i++) {
     sprintf(resultString, "TIME; %d ; %d ; %d ; %s\n",i,1,2,temp->stats->mboxFileName);
     fwrite(resultString, strlen(resultString), 1, pipeFD);
    }

    remove_node(temp);
    break;
   }
   temp = temp->next;
  }
  printf("done printing from sigchld \n");
 }
 return;
}

the output for my MAIN process is this:

MAIN PROCESS 16214 created WORKER PROCESS 16220 for file class.sp10.cs241.mbox
pidafdfaddf: 16214
stuff
stuff
inside if
done printing from sigchld 
MAIN PROCESS 16214 created WORKER PROCESS 16221 for file class.sp10.cs225.mbox
pidafdfaddf: 16214
stuff
stuff
inside if
done printing from sigchld 

and the output for the MONITOR process is this:

MONITOR: pipe is open for reading
MONITOR PIPE: TIME; 0 ; 1 ; 2 ; class.sp10.cs225.mbox
MONITOR PIPE: TIME; 0 ; 1 ; 2 ; class.sp10.cs225.mbox
MONITOR PIPE: TIME; 0 ; 1 ; 2 ; class.sp10.cs241.mbox
MONITOR: end of readpipe 

( I've taken out repeating lines so I don't take up so much space )

Thanks, Hristo

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