c - Can I cast into struct?

Question

EDIT - question is answered in comments.

I've been browsing cppreference.com and found a certain piece of code and ended up with the following after a little elaboration on it:

#include <stdio.h>

struct T { double a[4] };

struct T f(void) { return (struct T){3.15}; }    //Is that casting into struct T?? 
                                                 //But isn't casting into non-scalar not possible?

int main (void)
{
    double d = *f().a;                           //What?
    printf("%f
", d);
}

The question that relates to the topic is on the line with the first comment. I do kinda understand what's happening (i guess) but the syntax is not clear for me - could someone elaborate on it please?

Additional question (if possible to have two) is about the line with the second comment - so, i can use a return value of a function just as is in an expression, like in a given example?

Answer 1

等待大神答复