#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>

int main(void)
{
	int var = 0;
  
	printf("PID(Father)=%d, PPID=%d, var=%d\n", getpid(), getppid(), var);
  
	if ( fork() == -1 )
	{
		fprintf( stderr, "fork() failed!\n" );
	}
	else
	{
		var++;
		printf("PID=%d, PPID=%d, var=%d\n", getpid(), getppid(), var);
		if ( fork() == -1 )
		{
			fprintf( stderr, "Error at 2nd fork()!\n");
		}
		else
		{
			var++;
			printf("PID=%d, PPID=%d, var=%d\n", getpid(), getppid(), var);
		}
	}
	return 0;
}