C:重新定义“结构" [英] C : redefinition of ‘struct'

问题描述

我在重新定义结构体时遇到了麻烦.为了解释我的问题，我将考虑 4 个文件.

I'm in trouble with the Warning redefinition of struct. To explain my problem I will consider 4 files.

• 接口.c
• 解析器.h
• Auth.h
• 信息.h

Interface.c

    #include "Auth.h"
    #include "Info.h"

/* some code here */

解析器.h

struct ParsedAuthResponse {
   char *name;
   char *key;
};

struct ParsedInfoResponse {
   char *name;
   char *message;
};
void auth_parser(char* serverResponse,struct ParsedAuthResponse *response_a);
void scrobble_parser(char* serverResponse, int* scrobbleParsedparsedResponse);
void love_unlove_parser(char* serverResponse, int* loveUnloveParsedResponse);
void getInfo_parser(char* serverResponse,struct ParsedInfoResponse *responseP);

Auth.h

#include "parser.h"
functionX(int a, struct ParsedAuthResponse *response);
/* some code here */

Info.h

#include "parser.h"
functionY(int a, struct ParsedInfoResponse *response);
/* some code here */

当我在 Interface.c 中不包含 Info.h 或 Auth.h 时，没有问题.

When I don't include Info.h or Auth.h in Interface.c there is no problem.

推荐答案

你需要添加一个保护来防止 Parser.h 被包含两次，就像这样:

You need to add a guard that prevents Parser.h to be included twice, like this :

#ifndef PARSER_H
#define PARSER_H
struct ParsedAuthResponse {
   char *name;
   char *key;
};

struct ParsedInfoResponse {
   char *name;
   char *message;
};
void auth_parser(char* serverResponse,struct ParsedAuthResponse *response_a);
void scrobble_parser(char* serverResponse, int* scrobbleParsedparsedResponse);
void love_unlove_parser(char* serverResponse, int* loveUnloveParsedResponse);
void getInfo_parser(char* serverResponse,struct ParsedInfoResponse *responseP);
#endif

因为每次编写指令 #include "Parser.h" 时，Parser.h 的内容都会简单地复制粘贴到包含位置.这意味着您将同时声明两个结构.

Because each time you write the instruction #include "Parser.h" the content of Parser.h will simply be copy-pasted at the include location. This means that you will have both structures declared twice.

使用 ifndef 可以防止它被多次复制粘贴.

With the ifndef you prevent it from being copy-pasted more than once.

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