#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

int main(int argc, char **argv)
{
	pid_t          pid;

	printf("Parent process PID[%d] start running...\n", getpid() );

	pid = fork();
	if(pid < 0)
	{
		printf("fork() create child process failure: %s\n", strerror(errno));
		return -1;
	}
	else if( pid == 0 )
	{
		printf("Child process PID[%d] start running, my parent PID is [%d]\n", getpid(), getppid());
		return 0;
	}
	else // if( pid > 0 )
	{ 
		printf("Parent process PID[%d] continue running, and child process PID is [%d]\n", getpid(), pid);
	       	return 0;
	}
}