Question

我对c中的结构感到困惑。我正在尝试创建一个.h文件，其中包含我将使用的所有结构。我创建了structs.h

#include <ucontext.h>

#include <string.h>
#include <stdio.h>
#include <stdlib.h>



struct TCB_t;

typedef struct
{
    struct TCB_t * next;
    struct TCB_t * previous;
    ucontext_t context;
    int val;
}TCB_t;

我的TCB.h文件

#include "structs.h"



int count =0;
struct TCB_t *RunQ = NULL;
struct TCB_t *ptr = NULL;

void init_TCB (struct TCB_t *tcb, void *function, void *stackP, int stack_size, int *arg)
{
    memset(tcb, '\0', sizeof(struct TCB_t));
    getcontext(&tcb->context);
    tcb->context.uc_stack.ss_sp = stackP;
    tcb->context.uc_stack.ss_size = (size_t)stack_size;
    makecontext(&tcb->context, function, 1, arg);

}

当我跑步时，我得到以下错误。

Description Resource    Path    Location    Type
Field 'ss_size' could not be resolved   TCB.h   /projThree/src  line 14 Semantic Error


Description Resource    Path    Location    Type
Field 'ss_sp' could not be resolved TCB.h   /projThree/src  line 13 Semantic Error


Description Resource    Path    Location    Type
Field 'uc_stack' could not be resolved  TCB.h   /projThree/src  line 13 Semantic Error


Description Resource    Path    Location    Type
Field 'uc_stack' could not be resolved  TCB.h   /projThree/src  line 14 Semantic Error


  Description   Resource    Path    Location    Type
Symbol 'NULL' could not be resolved TCB.h   /projThree/src  line 6  Semantic Error


Description Resource    Path    Location    Type
Symbol 'NULL' could not be resolved TCB.h   /projThree/src  line 7  Semantic Error

如果我将struct fron structs.h移动到TCB.h，那么错误就会消失。为什么TCB.h不能访问structs.h中的结构，因为我包含了＃34; structs.h＆＃34;在页面顶部？

Answer 1

问题在于您已声明某处有struct TCB_t，并且您已为无标签（匿名）{{1}定义了名为typedef的{{1}} }}类型，但您尚未定义类型TCB_t。

~~struct~~

你需要写下这个：

struct TCB_t

或者这个：

struct TCB_t;    // There is, somewhere, a type struct TCB_t

typedef struct   // This is an anonymous struct, not a struct TCB_t
{
    struct TCB_t * next;
    struct TCB_t * previous;
    ucontext_t context;
    int val;
} TCB_t;         // This is a typedef for the anonymous struct

最终都有typedef struct TCB_t TCB_t; struct TCB_t { TCB_t *next; // Optionally struct TCB_t TCB_t *previous; // Optionally struct TCB_t ucontext_t context; int val; };和普通类型typedef struct TCB_t { struct TCB_t *next; struct TCB_t *previous; ucontext_t context; int val; } TCB_t;，这是struct TCB_t的别名。

请注意，TCB_t后缀正式保留供实现（编译器和支持库）使用。您可能会遇到自己使用它的问题（但是在更改名称之前可能不会很晚）。

编译错误的原因是编译器没有被告知struct TCB_t包含的内容，因此您无法访问_t成员，因此不能访问其中的字段struct TCB_t成员。

C和.h文件中的结构

1 个答案: