TL;DR: void f(int *a) { int **p = &a; **p = 1; // the same as *a = 1; } Making a concise explanation of how exactly the third derefer

TL;DR: void f(int *a) { int **p = &a; **p = 1; // the same as *a = 1; } Making a concise explanation of how exactly the third dereferencing disappeared is left as a further exercise for the reader.