c++11 - What is the meaning of auto when using C++ trailing return type?

Question

Instead of usual

void foo (void ) {
    cout << "Meaning of life: " << 42 << endl;
}

C++11 allows is an alternative, using the Trailing Return

auto bar (void) -> void {
    cout << "More meaning: " << 43 << endl;
}

In the latter - what is auto designed to represent?

Another example, consider function

auto func (int i) -> int (*)[10] {

}

Same question, what is the meaning of auto in this example?

Answer 1

In general, the new keyword auto in C++11 indicates that the type of the expression (in this case the return type of a function) should be inferred from the result of the expression, in this case, what occurs after the ->.

Without it, the function would have no type (thus not being a function), and the compiler would end up confused.