c - 错误 : Redeclaration with no linkage

Question

#include<stdio.h>
int x=13; // forcing space allocation 
int x; 
int main(){
  printf("%d\n",x); 
}

上面的代码可以编译，但下面的代码不能。为什么？

#include<stdio.h> 
int main(){
  int x=13; // forcing space allocation 
  int x;
  printf("%d\n",x); 
}

有人告诉我 int x ;编译器可以根据上下文将其解释为声明或定义。我可以在第一种情况(全局情况)中看到这一点，但在第二种情况下会发生什么。

Answer 1

Quoting:

You can't have two global variables with the same name in C program. C might allow multiple definitions in the same file scope through the tentative definition rule, but in any case all definitions will refer to the same variable.