克隆()系统调用C和共享

我正在尝试使用clone()系统调用来创建一个与父进程共享资源的线程.
在本书中,我读到如果我使用以下标志,我将能够这样做：
CLONE_VM | CLONE_FILES | CLONE_SIGHAND | CLONE_FS

但似乎变量没有被分享.

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <linux/sched.h>
#include <String.h>
#define STACK_SIZE 65536
#define BUFSIZE 200
int n = 5;
int Child(void *);
int main() {
    pid_t pid;
    char *stack;
    stack = malloc(STACK_SIZE);
    pid = clone(Child,stack + STACK_SIZE,CLONE_SIGHAND|CLONE_FS|CLONE_VM|CLONE_FILES);
    wait(null);
    char buf[BUFSIZE];
    sprintf(buf,"BACk to parent: Value of n: %d\n",n);
    write(1,buf,strlen(buf));
    return 0;
}
int Child(void *args) {
    n += 15;
    char buf[BUFSIZE];
    sprintf(buf,"In child: Value of n: %d\n",n); 
    write(1,strlen(buf));
}

输出也在不断变化.我糊涂了.

int n = 5;
int Child(void *);
int main() {
    int n = 5;