结构的C不完整类型

C incomplete type for struct

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我正在尝试采用RRHEAD，在RRHEAD处设置一个新的RCB点作为下一个点，在新的RCB处设置RRHEAD点作为前一个点。

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typedef struct{
int sequence_number;
int file_descriptor;
FILE *requested_file;
int bytes_remaining;
int quantum;
struct RCB *next;
struct RCB *prior;
} RCB;

typedef struct RCB RCB;

RCB *RRhead = NULL;

static void admit_to_scheduler_RR(int fd, FILE *fin){
int sequence_counter, new_bytes_remaining, new_quantum = 0;
RCB new_rcb = {sequence_counter, fd, fin, new_bytes_remaining, new_quantum, RRhead, NULL};
RRhead->prior = &new_rcb;
RRhead = &new_rcb;
sequence_counter++;
}

产生以下错误：

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sws.c: In function ‘admit_to_scheduler_RR’:
sws.c:318:10: error: variable ‘new_rcb’ has initializer but incomplete type
struct RCB new_rcb = {sequence_counter, fd, fin, new_bytes_remaining, new_quantum, RRhead, NULL};
^
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:10: warning: excess elements in struct initializer [enabled by default]
sws.c:318:10: warning: (near initialization for ‘new_rcb’) [enabled by default]
sws.c:318:14: error: storage size of ‘new_rcb’ isn’t known
struct RCB new_rcb = {sequence_counter, fd, fin, new_bytes_remaining, new_quantum, RRhead, NULL};
^
sws.c:319:9: error: dereferencing pointer to incomplete type
RRhead->prior = &new_rcb;
^

我不知道为什么我会收到过量元素的警告。我没有正确初始化新的接收器吗？我是否需要创建它，然后将所有字段设置为我想要的？

我相信这一切都是因为新的接收器有一个"不完整的类型"。大多数谷歌搜索都表明这是因为编译器不知道RCB的大小。这似乎表明我需要将这个结构定义放入一个头中。这是绝对必要的吗？

相关讨论

在第一个声明中，您声明RCB是使用typedef的struct。之后，你直接说，‘顺便说一句，RCB是struct RCB的意思，这在这一点上是没有定义的！(要想生存下去，你就得说struct RCB { ... };。)

基本上，删除typedef struct RCB RCB;，消除相关错误，但会弹出新的错误。

尝试如下操作：

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typedef struct RCB RCB;
strutc RCB {
....

C中的"标记"名称空间(与struct和union一起提供)不同于标识符名称空间。通过typedef，还可以将标识符RCB与类型struct RCB关联起来。

尝试将结构更改为以下值(即删除typedef关键字)：

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struct RCB {
int sequence_number;
int file_descriptor;
FILE *requested_file;
int bytes_remaining;
int quantum;
struct RCB *next;
struct RCB *prior;
};

在这个答案中，可以读取更多的信息来区分C++中的"结构"和"TyPulfStrut"之间的区别。.

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

typedef struct RCB RCB;

typedef struct RCB {
int sequence_number;
int file_descriptor;
FILE *requested_file;
int bytes_remaining;
int quantum;
RCB *next;
RCB *prior;
} RCB;

RCB new_rcb = {11, 21, NULL, 31, 41, NULL, NULL};;

static void admit_to_scheduler_RR(int fd, FILE *fin) {

int sequence_counter = 0;
int new_bytes_remaining, new_quantum = 0;
RCB *RRhead = &new_rcb;
RRhead->prior = &new_rcb;
sequence_counter++;
}

int main(int argc, char *argv[]) {

admit_to_scheduler_RR(1, NULL);
return 0;
}

要修复您的错误，您需要将代码更改为与上面类似的东西，它使用您的数据结构和编译。