What is the lifetime of compound literals passed as arguments?

Question

This compiles without warnings using clang.

typedef struct {
  int option;
  int value;
} someType;

someType *init(someType *ptr) {
  *ptr = (someType) {
           


        

Answer 1

Yu Hao has answered with the standard, now some vulgarization.

Whenever you see a compound literal like:

struct S *s;
s = &(struct S){1};

you can replace it with:

struct S *s;
struct S __HIDDEN_NAME__ = {1};
s = &__HIDDEN_NAME__;

So:

struct S {int i;};
/* static: lives for the entire program. */
struct S *s = &(struct S){1};

int main() {
   /* Lives inside main, and any function called from main. */
   s = &(struct S){1};

   /* Only lives in this block. */
   {
       s = &(struct S){1};
   }
   /* Undefined Behavior: lifetime has ended. */
   s->i;
}