```c
int sf_error_get_print(void);
```

is an ISO C prototype declaration of a function taking no arguments.

```c
int sf_error_get_print();
```

is a K&R C declaration of a function taking any number of arguments, allowed in ISO C for backward compatibility only. It turns typechecking on the arguments off, so you can call

```c
sf_error_get_print("foo", 1, NULL);
```

without a warning and get undefined behavior.