multiple-indirection – Tarik Billa

What is double star (eg. NSError **)?

April 18, 2023 by Tarik

A “double star” is a pointer to a pointer. So NSError ** is a pointer to a pointer to an object of type NSError. It basically allows you to return an error object from the function. You can create a pointer to an NSError object in your function (call it *myError), and then do something … Read more

Double pointer const-correctness warnings in C

March 11, 2023 by Tarik

The reason why const can only be added one level deep is subtle, and is explained by Question 11.10 in the comp.lang.c FAQ. Briefly, consider this example closely related to yours: const int i; int *p; int const **z = &p; *z = &i; /* Now p points to i */ C avoids this problem … Read more