4 ms·

I don't keep up with the latest C shenanigans, cuz I like C the way it was, but have they change something where "pointer to an array[5]" is a meaningful distin

I don't keep up with the latest C shenanigans, cuz I like C the way it was, but have they change something where "pointer to an array[5]" is a meaningful distinction to draw? I mean, "a pointer to an array of X" is simply "a pointer to X" and using hungarian notation, you can encode the knowledge "this pointer can be incremented" into its name. and typedef'ing *function declarations? who has families of functions with the same type signatures that they want to point to?

CuriousCosmic 2y ago
> but have they change something where "pointer to an array[5]" is a meaningful distinction to draw This has been a meaningful distinction since at least C99. > "a pointer to an array of X" is simply "a pointer to X" They aren't actually the same. The former can be decayed into the latter but they aren't actually equivalent and you'll get type mismatches if you try to treat them as the same thing. > who has families of functions with the same type signatures that they want to point to An example is callbacks or handlers for responding to interrupt requests. A lot of hardware interface code relies on typedef-ed function decls because very often you are passing user side functions through your interface so that you can stash those function pointers somewhere and invoke them when some event occurs.
- deleted 2y ago
  [deleted]
kelnos 2y ago
> "a pointer to an array of X" is simply "a pointer to X" I don't believe these two are the same. An "array of X" indeed decays to a "pointer to X". But a "pointer to an array of X" is something else. E.g. int foo[3]; // array of int int *foo; // pointer to int int *foo[3]; // pointer to array of int Perhaps the first two are what you mean, though, and this is just a terminology issue.
- fsckboy 2y ago
  int *foo[3]; // pointer to array of int that's an array of 3 pointers to ints. if you pass foo as an argument you get a pointer to a pointer to an int (with knowledge if you can hang onto it that there are more pointers to ints lined up in memory)
  - tpoacher 2y ago
    Yes, but this is different: int (* foo) [3] This is a pointer to an array of 3 ints. And you could pass this to an appropriate function as an argument, to pass the whole array, not just a decayed pointer. And more generally, I'd group things as unambiguously as possible even in your example: int * (foo [3]) to make the intent clearer

CuriousCosmic 2y ago

> but have they change something where "pointer to an array[5]" is a meaningful distinction to draw This has been a meaningful distinction since at least C99. > "a pointer to an array of X" is simply "a pointer to X" They aren't actually the same. The former can be decayed into the latter but they aren't actually equivalent and you'll get type mismatches if you try to treat them as the same thing. > who has families of functions with the same type signatures that they want to point to An example is callbacks or handlers for responding to interrupt requests. A lot of hardware interface code relies on typedef-ed function decls because very often you are passing user side functions through your interface so that you can stash those function pointers somewhere and invoke them when some event occurs.

deleted 2y ago
[deleted]

kelnos 2y ago

> "a pointer to an array of X" is simply "a pointer to X" I don't believe these two are the same. An "array of X" indeed decays to a "pointer to X". But a "pointer to an array of X" is something else. E.g. int foo[3]; // array of int int *foo; // pointer to int int *foo[3]; // pointer to array of int Perhaps the first two are what you mean, though, and this is just a terminology issue.

fsckboy 2y ago
int *foo[3]; // pointer to array of int that's an array of 3 pointers to ints. if you pass foo as an argument you get a pointer to a pointer to an int (with knowledge if you can hang onto it that there are more pointers to ints lined up in memory)
- tpoacher 2y ago
  Yes, but this is different: int (* foo) [3] This is a pointer to an array of 3 ints. And you could pass this to an appropriate function as an argument, to pass the whole array, not just a decayed pointer. And more generally, I'd group things as unambiguously as possible even in your example: int * (foo [3]) to make the intent clearer