Question

我正在尝试在c中编译此代码。首先，我将此结构放在一个单独的源文件中，以便像“类”（dir.h）

一样使用它

//Structure
typedef struct s_dirobject {
    int noteid;
    char title[20];
    int bytes;
    char head[20];
    bool is_dir;
    struct s_dirobject* next;
} dirobject;

//Ops
void add_dirobject(dirobject* myDirobject,int num_dirobject, char title[20], int is_dir,     int bytes, char head[20]);
int get_dirobject_noteid(dirobject* myDirobject,int num_note);
char* get_dirobject_title(dirobject* myDirobject,int num_note);
int get_dirobject_bytes(dirobject* myDirobject,int num_note);
char* get_dirobject_head(dirobject* myDirobject,int num_note);
bool isdir(dirobject* myDirobject, int num_note);
int get_dirobjects_len(dirobject* myDirobject);
void clear_dir(dirobject* myDirobject);
void init_dir(dirobject* myDirobject);

第二，我有通信源从远程文件系统检索目录的内容，并填充对象（comms.c）

#include "notebook.h"
#include "dir.h"

dirobject* temporaldirobjects;

...

init_dir(temporaldirobjects);
while(cond) {
    //Add retrieved item to the directory
    add_dirobject(temporaldirobjects, index, title, is_dir, bytes, "");
}
//When done retrieving the contents from the source i do instantiate the notebook_window
notebook_init(source, path, temporaldirobjects);

最后，我的笔记本窗口界面将如下所示。（notebook.h）

#include "dir.h"
void notebook_init(char* source, char* path, dirobject* contents);
void notebook_deinit();

及其实现（notebook.c）

void notebook_init(char* source, char* path, dirobject* contents) {

    // Fill the vars
    this_window_source=source;
    this_window_path=path;
    this_window_dirobjects=contents;

    ...
}

当我按原样编译此代码时，我收到错误消息

../src/dir.h:13:16: error: redefinition of 'struct s_dirobject'
In file included from ../src/notebook.h:12:0,
                 from ../src/comms.c:25:
../src/dir.h:13:16: note: originally defined here
In file included from ../src/comms.c:27:0:
../src/dir.h:20:3: error: conflicting types for 'dirobject'
In file included from ../src/notebook.h:12:0,
                 from ../src/comms.c:25:
../src/dir.h:20:3: note: previous declaration of 'dirobject' was here
In file included from ../src/comms.c:27:0:
../src/dir.h:23:6: error: conflicting types for 'add_dirobject'
In file included from ../src/notebook.h:12:0,
                 from ../src/comms.c:25:
../src/dir.h:23:6: note: previous declaration of 'add_dirobject' was here
...

因为comms库包含dir.h和notebook.h，而notebook.h也是如此。如果我删除了notebook.h中的include，我还有另外一个错误：

In file included from ../src/comms.c:25:0:
../src/notebook.h:14:46: error: unknown type name 'dirobject'

我怎么能实现这个目标？我想尽可能保持清洁代码。

Answer 1

您在文件comms.c

中添加了两个标头

#include "notebook.h"
#include "dir.h"

标题notebook.h又包含标题dir.h

#include "dir.h"
void notebook_init(char* source, char* path, dirobject* contents);
void notebook_deinit();

结果，结构在同一编译单元中定义了两次。您必须提供每个标头在每个编译单元中只包含一次。要做到这一点，你必须提供标题的quars。例如

#ifndef DIR_H
#define DIR_H

//Structure
typedef struct s_dirobject {
    int noteid;
    char title[20];
    int bytes;
    char head[20];
    bool is_dir;
    struct s_dirobject* next;
} dirobject;

//...

#endif

或者如果编译器支持#pragme一次，那么你可以使用它。

Answer 2

通常，c中有多个声明，但多个定义不是。在您的代码中，您多次包含dir.h，导致重新定义struct s_dirobject。阅读关于＆＃34; Header guard＆＃34;或者＆＃34;包括警卫＆＃34;。 here。希望这可以通过重新定义解决您的主要问题。

将struct指针作为参数传递

2 个答案: