C结构体的不完整类型

我试图采用RRhead，在RRhead上有一个新的RCB点，因为它是下一个，并且在新的RCB处有RRhead点，因为它是先前的点。C结构体的不完整类型

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：

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; 
     ^

我不知道为什么我收到了多余的元素警告线索。我没有正确初始化new_rcb吗？我是否需要创建它，然后将所有字段设置为我想要的？

我相信这一切都与new_rcb有一个“不完整的类型”有关。大多数使用Google表示这是因为编译器不知道RCB的大小应该是多少。它似乎表明我需要将此结构定义放入一个标题中。这是绝对必要的吗？

来源

2016-06-13 Daniel Paczuski Bak

'typedef struct RCB RCB;'尝试删除该文件 –

删除该文件会导致此函数发生不同的错误。 –

在第一个声明中，您声明RCB是struct使用typedef。直接后来，你说，'顺便说一句，RCB意味着struct RCB'，这是没有定义在这一点！（对于存在的，你不得不说struct RCB { ... };代替。）

基本上，删除typedef struct RCB RCB;这将摆脱对相关错误的，但新会弹出。

来源

2016-06-13 05:52:33 thriqon

尝试你的结构更改为以下（即删除typedef关键字）：

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

的更多信息可以在这个答案读给Difference between 'struct' and 'typedef struct' in C++?。

来源

2016-06-13 05:58:33 Elyasin

尝试这样：

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

“标签”命名空间中的C（与struct和union推出）是从标识符名字空间不同。使用typedef，您还可以将标识符RCB与类型struct RCB关联。

来源

2016-06-13 05:58:45

#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; 
}

要修复你的错误，你需要更改您的代码类似于上面的东西，它使用你的数据结构和编译。

来源

2016-06-13 06:08:34

C结构体的不完整类型

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