在C中链接多个头文件

Question

我正在处理一个包含 4 个文件的项目：main.c lists.c hash.c structs.c 以及相应的 .h 文件。问题是在 lists.c 中我需要 link structs.h。它给我一个错误，说 structs.c 中的函数与 structs.h 文件中该函数的声明冲突。

在lists.h中我做#include "structs.h and in lists.c I do #include "lists.h" 我没有得到任何错误。在 stucts.c 我做 #include "structs.h"

lists.h:

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

typedef struct list{
   Instr head;
   struct list *tail;
} *ILIST;

ILIST mkList(Instr, ILIST);

lists.c:

#include "lists.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

ILIST mkList(Instr n, ILIST l1) {
  ILIST l = malloc(sizeof(struct list));
  l->head = n;
  l->tail = l1;
  return l;
}

structs.h:

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

typedef enum  {START, QUIT, ATRIB, ADD, SUB, MUL, PRINT, READ, IF, GOTO, LABEL} OpKind;
typedef enum {INT_CONST, STRING, EMPTY} ElemKind;

typedef struct{
  ElemKind kind;
  union
  {
    int val;
    char* name;
  }content;
} Elem;

structs.c:

#include "structs.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

我遇到这样的错误

In file included from lists.h:1:0,
                 from main.c:3:
structs.h:5:16: error: redeclaration of enumerator ‘START’
 typedef enum  {START, QUIT, ATRIB, ADD, SUB, MUL, PRINT, READ, IF, GOTO, LABEL} OpKind;
                ^~~~~

In file included from main.c:1:0:
structs.h:5:16: note: previous definition of ‘START’ was here
 typedef enum  {START, QUIT, ATRIB, ADD, SUB, MUL, PRINT, READ, IF, GOTO, LABEL} OpKind;
                ^~~~~

Answer 1

Header Guards

只包括像这样的头球后卫：


#ifndef __GUARD_STRUCTS__
#define__GUARD_STRUCTS__

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

typedef enum  {START, QUIT, ATRIB, ADD, SUB, MUL, PRINT, READ, IF, GOTO, LABEL} OpKind;
typedef enum {INT_CONST, STRING, EMPTY} ElemKind;

typedef struct{
  ElemKind kind;
  union
  {
    int val;
    char* name;
  }content;
} Elem;

#endif

在C中链接多个头文件

Linking multiple header files in C

c

header-files