应该定义和声明是否匹配？

问题描述：

在我.h文件中我有

extern int a[4];

在我的.c文件我有

int a[10];

那么，有没有任何问题，这件事？

So are there any issues with this?

宣言和定义大小事务？不是吧？

Declaration and definition size matters? Not right?

如果我写的的sizeof（A）中的文件之一，会是怎样的输出？
这是不确定的行为？

If I write sizeof(a) in one of the files, what will be the output? Is this undefined behavior?

答

如果您在您的源代码头文件文件的两个声明 A 必须具有的同的类型为C说：

If you include your header file in your source file the two declarations of a must have the same type as C says:

（C11，6.7p4）在同一范围内的所有声明指向同一对象或函数应规定兼容的类型。

(C11, 6.7p4) "All declarations in the same scope that refer to the same object or function shall specify compatible types."

即使这两个声明有两种翻译单位，他们需要具备的相同的类型：

Even if the two declarations are in two translation units, they need to have the same type:

（C11，6.2.7p2）是指同一对象或函数的所有声明应具有兼容的类型;否则，其行为是未定义

(C11, 6.2.7p2) "All declarations that refer to the same object or function shall have compatible type; otherwise, the behavior is undefined."