[C语言]二维指针与一维指针

void test1(char *pt){
    pt =(char*)calloc(10,1);
    memcpy(pt,"Nice_\n",6);
}

void test2(char**pt){
    *pt =(char*)calloc(10,1);
    memcpy(*pt,"Good_\n",6);
}

void main(void){
    char *point=0;
    test1(point);
    printf(point); //输出: 空白
    test2(&point);
    printf(point); //输出: Good_
}

函数test1和test2都是尝试将传入的参数做赋值修改, 但是test1无效,而test2成功, 可见要修改传入的指针指向的内容需要二维指针!