所以我在c中有一个链表。我正在尝试使用 Linux 中的模块来编译它。因此,在我的链接列表中,我输入了 6 个人。上面有年月日和名字。在程序中,我输入了 6 个人及其属性。当我尝试横向链接列表时,它无法正确编译。我的代码即将完成,但不知道我到底在哪里搞砸了。
我收到的错误消息:
implicit declartion of funciton 'print'
assignment from incompatible pointer type
expected ; before while
ISO c90 forbids mixed declarations and code
expected expression before',' token
'next' undeclared
invalid type argument of unary '*"
compiling through terminal and the erro i'm getting are: warning control reaches end non-void function. – black 7 mins ago
Expted declaration or statement at end of input. – black 7 mins ago
in expantion of macro 'Module_License – black 6 mins ago
warning 'alias' attribute ignored. – black 5 mins ago
Error: invalid storage class for function – black 5 mins ago
error: expected identifier before '=' token *birthday_list->NULL; – black 5 mins ago
error: struct birthday has no member named next – black 4 mins ago edit
You have a lot of mistake in your code such as ptr=&birthday_list (forgot semicolon in the end of the line. – ymonad just now
所以我试图让它到达输出的位置: It loads the module and states the six people then removes the people in the list.
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/slab.h>
struct birthday
{
int month;
int day;
int year;
char *name;
struct list_head list;
};
/**
* The following defines and initializes a list_head object named birthday_list
*/
static LIST_HEAD(birthday_list);
int simple_init(void)
{
struct birthday *person;
/* Creating Person 1 */
person = kmalloc(sizeof(*person), GFP_KERNEL);
person->month = 8;
person->day = 12;
person->year = 1993;
person->name = "Aaron";
INIT_LIST_HEAD(&person->list);
list_add_tail(&person->list, &birthday_list);
/* Creating Person 2 */
person = kmalloc(sizeof(*person), GFP_KERNEL);
person->month = 4;
person->day = 15;
person->year = 1993;
person->name = "Fish";
INIT_LIST_HEAD(&person->list);
list_add_tail(&person->list, &birthday_list);
/* Creating Person 3 */
person = kmalloc(sizeof(*person), GFP_KERNEL);
person->month = 3;
person->day = 29;
person->year = 1983;
person->name = "js";
INIT_LIST_HEAD(&person->list);
list_add_tail(&person->list, &birthday_list);
/* Creating Person 4 */
person = kmalloc(sizeof(*person), GFP_KERNEL);
person->month = 7;
person->day = 25;
person->year = 1999;
person->name = "Mark";
INIT_LIST_HEAD(&person->list);
list_add_tail(&person->list, &birthday_list);
/* Creating Person 5 */
person = kmalloc(sizeof(*person), GFP_KERNEL);
person->month = 7;
person->day = 19;
person->year = 1992;
person->name = "Leah";
INIT_LIST_HEAD(&person->list);
list_add_tail(&person->list, &birthday_list);
/* Creating Person 6 */
person = kmalloc(sizeof(*person), GFP_KERNEL);
person->month = 1;
person->day = 11;
person->year = 1991;
person->name = "Han";
INIT_LIST_HEAD(&person->list);
list_add_tail(&person->list, &birthday_list);
printk(KERN_INFO "Loading Module\n");
struct birthday *ptr;
list_for_each_entry(ptr, &birthday_list, list) {
/* On each iteration ptr points */
/* to the next birthday struct */
if(ptr ==NULL){
print("List is empty");
}else{
ptr=&birthday_list
while(ptr!=NULL){
ptr=ptr->list;
}
}
return 0;
}
void simple_exit(void) {
printk(KERN_INFO "Removing Module\n");
struct birthday *ptr, *next
list_for_each_entry_safe(ptr, next, *birthday_list, list) {
while(ptr!=NULL){
ptr->next=*birthday_list->next;
*birthday_list->=NULL;
}
list_del(&ptr->list);
kfree(ptr);
}
}
module_init(simple_init);
module_exit(simple_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Kernel Data Structures");
MODULE_AUTHOR("SGG");
最佳答案
您的代码中有几个问题:
- 在
simple_exit
函数的第二行中,您忘记了行尾的;
。 - 在
simple_exit
函数中,有行ptr->next=*birthday_list->next;
,其中ptr
是指向结构生日
对象。不幸的是,structbirthday
对象没有next
成员。 - 在
simple_exit
函数中,有行*birthday_list->=NULL;
,这在语法方面是错误的。您想编写birthday_list = NULL;
或类似的内容吗? - 在
simple_init
函数末尾,您使用print
而不是printk
。 您的编译器提示
ISO c90 禁止混合声明和代码
。这基本上意味着,如果您使用遵守 C90 标准的编译器,则必须在执行“其他操作”之前声明所有变量。所以类似int i = 0; int j = 0; i = i + 5;
工作时
int i = 0; i = i + 5; int j = 0;
不是因为
j
是在“用i
完成某事”之后声明的。您可以在代码中执行类似的操作,例如在simple_init
函数中间声明structbirth *ptr;
。在这种情况下,您应该将此行移至simple_init
函数的开头。
代码中可能还有更多问题,但您可以先尝试修复这些问题。仔细阅读错误消息也是一个好主意,因为它们有时是不言自明的。
关于c - Linux中如何遍历链表?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/48493355/