在数组初始值设定项中有多余的元素可以吗？

Question

Usually when we initialize an array, we would probably do:

int arr[] = {1, 2, 3, 4, 5};

But is it ok to explicitly limit the length of the array as below? :

int arr[3] = {1, 2, 3, 4, 5};

Despite some warnings from the compiler, the executable doesn't seem to have any problems.

Answer 1

No, it's not OK. From C99, 6.7.8.2:

Constraints

1. No initializer shall attempt to provide a value for an object not contained within the entity being initialized.

In my read, this means that providing excess initializer elements is a constraint violation, so it invokes undefined behavior.