Question

I would like to know what happens when there are more initializers than array size, e.g. :

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

Of course, my compiler warns it. I expected undefined behavior, but I didn’t find any clause about it in C11 standard. So, did I miss something ?

Answer 1

The code is ill-formed in both C and C++.

C++11 §8.5.1[dcl.init.aggr]/6 states:

An initializer-list is ill-formed if the number of initializer-clauses exceeds the number of members or elements to initialize.

C11 §6.7.9/2 states:

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