访问结构中的数组会导致发出叮当声警告

Question

struct test{
   char c_arr[1];
};

test array[1] = {{1}};

test get(int index){
 return array[index];
}

int main(){
  char* a =  get(0).c_arr;
  return 0;
}

Compiling this with g++ has no warnings but with clang++ prints the following:

warning: temporary whose address is used as value of local variable 'a' will be destroyed at the end of the full-expression

Is this incorrect? does get(0).c_arr not return a pointer to a global array?

or does get(0) return a temporary variable and the compiler thinks c_arr is just an instance of it, and not global, by mistake?

Edit

Why passing this temp variable to a function works without warnings?

void call(char* in){}

int main(){
  call(get(0).c_arr);
  return 0;
}

Answer 1

get returns by-value, then get(0) does return a temporary which gets destroyed after the full expression, left a being a dangling pointer.

Note that the returned temporary test is copied from array[index] , including the array data member c_arr . a is supposed to point to the 1st element of the data member array c_arr of the temporary test , after the full expression (ie the ; in char* a = get(0).c_arr; ) the whole temporary test (and its data member c_arr ) is destroyed, then a becomes dangling.

If get returns by-reference then it'll be fine.

test& get(int index){
 return array[index];
}

EDIT

The code you added is fine. The temporary is destroyed after the full expression, ie after ; in call(get(0).c_arr); . The pointer passed to call remains valid inside call .