2 ms·

I've commonly seen it used for both. Really anything that the function will write to.

• masklinn 6y ago
  > I've commonly seen it used for both That's a good reason to rename one of them because they're completely different semantics and behaviour, and confusing one for the other is a direct route to segfault city.
  • comex 6y ago
    From another perspective, they're both performing the same operation on different types. With what you'd call "destination passing", like char *buf = malloc(128); snprintf(buf, 128, "hello"); the function is accepting a pointer to an uninitialized array of char, and initializing the array of char. With what you'd call an "out parameter", like char *buf; asprintf(&buf, "hello"); the function is accepting a pointer to an uninitialized pointer to array of char, and initializing the pointer. The caller still controls the allocation of storage for the pointer itself.
  • arka2147483647 6y ago
    At this point of the lifetime C-language, hoping for the commonly accepted terminology to change, is probably futile. Anyway, for out parameters, the common convention is: Caller provides one object for output: void callee(Obj *obj); Caller provides an array for output: void callee(Obj *obj, size_t obj_size); Caller provides an pointer, to which callee allocates a new object: void callee(Obj **obj)