C: Initialize structs as pointers only?

Question

Is there a way to ensure a struct object upon creation is always a pointer? ex: ``` typedef struct { int foo; } blah; blah a; // error blah* b; // ok ```

Accepted Answer

Sure - you just need to hide away the definition of the `struct` into its own translation unit away from prying eyes. Then, someplace else (and more public), just forward declare the structure:

```
typedef struct x blah;
```

`blah` in this case is an incomplete type, so anyone with access only to that declaration will only be able to create `blah *` objects, not full `blah` objects.

Another option is to change your typedef:

```
typedef struct
{
    int foo;
} *blah;
```

Now, `blah` is inherently a pointer type, and any declaration:

```
blah b;
```

Is in fact creating only a pointer. Since the `struct` itself is anonymous, there's no way to create one except through the pointer-only `typedef`.

C: Initialize structs as pointers only?

Solution

Problem