#include <sys/types.h> 		//pid_t
#include <unistd.h> 		//fork()
#include <sys/wait.h>		//waitpid
#include <stdio.h>		//printf...
#include <stdlib.h>		//exit()
//cntrl-proc1.c
int main(void)
{	
	pid_t pid;
	int status;

	pid=fork();
	if(pid!=0) {
		printf("pid1=%d\n",pid);
		wait(&status);printf("status1=%d\n",status);
		exit(0);
	}else{
		pid=fork();		if(pid==0) exit(1);
		printf("\tpid=%d ppid=%d\n",pid,getpid());
		wait(&status);printf("\tstatus=%d\n",status);
		pid=fork();		if(pid==0) exit(2);
		printf("\tpid2=%d\n",pid);
		wait(&status);printf("\tstatus2=%d\n",status);
		pid=fork();		if(pid==0) abort();
		printf("\tpid3=%d\n",pid);
		wait(&status);printf("\tstatus3=%d\n",status);
		pid=fork();		if(pid==0) status /= 0;
		printf("\tpid4=%d\n",pid);
		wait(&status);printf("\tstatus4=%d\n",status);
		exit(0);
	}
}