C全局结构指针

Question

我有一个在文件中声明的typedef'ed结构.我有一个指针,并希望在多个文件中使用它作为全局变量.有人可以指出我做错了什么吗？

fileA.h:

typedef struct
{
  bool                  connected;
  char                  name[20];
}vehicle;

extern vehicle *myVehicle;

fileA.c:

#include "fileA.h"
void myFunction(){
    myVehicle = malloc(sizeof(vehicle));
    myVehicle->connected = FALSE;
}

fileB.c:

#include "fileA.h"
void anotherFunction(){
   strcpy(myVehicle->name, "this is my car");
}

我得到的错误是:

fileA中引用了未定义的外部"myVehicle"

Answer 1

这是一个声明:

extern vehicle *myVehicle; /* extern makes this a declaration,
                              and tells the compiler there is
                              a definition elsewhere. */

添加定义:

vehicle *myVehicle;

到恰好一个.c文件.