c++ - 预定义struct，报错

Question

我有三个来源:代码处理.h

typedef enum {typeBool, typeVarDeclaration, typeFuncDeclaration } nodeEnum;
typedef struct varDeclarationNodeType{
    char *varName;                  /* Var Name */
    int defaultType;                /* default value type*/
    int defaultValue;               /* default value*/
    int ndim;                       /* number of dimensions */
    int *dim;                       /* dimensions (expandable) */
} varDeclarationNodeType;

typedef struct {
    char *funcName;
    std::vector<char *> *args;       /* arguments (expandable) */
} funcDeclarationNodeType;

typedef struct {
    bool value;
} boolNodeType;

typedef struct nodeTypeTag {
    nodeEnum type;              /* type of node */

    union {
        boolNodeType boolVal;   /* bools */
        varDeclarationNodeType varDeclaration;      /*var declarations*/
        funcDeclarationNodeType funcDeclaration;
    };
} nodeType;

代码处理.cpp

#include "codeproc.h"
#include "codecontext.h"
...

代码上下文.h

#include "codeproc.h"
class Function{
public:
    Function();
    ~Function();
    map<string, Value*> locals;     //local variables
    map<string, Value*> args;       //arguments
    int numOfArgs;                  //number of arguments
    nodeType *entryPoint;           //first statement in function
    Value *lastCallResult;          //variable that contain result from last call
};

错误:

codeproc.h error: 'varDeclarationNodeType' has a previous declaration as 'typedef struct varDeclarationNodeType varDeclarationNodeType'

就这样。这种情况如何预定义struct？

Answer 1

这部分

typedef struct varDeclarationNodeType{
    ...
} varDeclarationNodeType;

应该是这样的

typedef struct{
    ...
} varDeclarationNodeType;

并且您应该在头文件中使用头文件保护或#pragma once。