#include <pthread.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>

#define NUM_THREADS     100

void sigchld_handler(int s)
{
	while(wait(NULL) > 0);
}

void *PrintHello(void *threadid)
{
	pid_t pid;
	struct sigaction reapchildren;

	memset(&reapchildren, 0, sizeof(reapchildren));
	reapchildren.sa_handler = sigchld_handler;;
	reapchildren.sa_flags = SA_NOCLDWAIT;

	if (sigaction(SIGCHLD, &reapchildren, 0) == -1) {
		perror("sigaction");
		exit(1);
	}
	for(;;){
		pid = vfork();
		if(pid==0)
			_exit(0);
	}
	return (0);
}

int main (int argc, char *argv[])
{
   pthread_t threads[NUM_THREADS];
   int rc, t;

   for(t=0; t<NUM_THREADS; t++){
      rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
      if (rc)
         exit(-1);
   }
   return (0);
}