---
title: OSOrderFunction
framework: kernel
role: pseudoSymbol
path: kernel/osorderedset/osorderfunction
---

# OSOrderFunction

The sorting function used by an OSOrderedSet to order objects.

## Declaration

```occ
typedef SInt32 ( *OSOrderFunction)(
   const OSMetaClassBase *obj1,
   const OSMetaClassBase *obj2,
   void *context);
```

## Parameters

- `obj1`: An object from the ordered set. May be NULL.
- `obj2`: The object being ordered within the ordered set. May be NULL.
- `context`: A pointer to a user-provided context. May be NULL.

## Return Value

Return Value A comparison result of the object: a negative value if obj2 should precede obj1, a positive value if obj1 should precede obj2, and 0 if obj1 and obj2 have an equivalent ordering.