Creates a key that can be used to receive notifications when the
Host entity changes.
- macOS 10.2+
The allocator that should be used to allocate memory for this key. This parameter may be
NULLin which case the current default allocator is used. If this value is not a valid
CFAllocator, the behavior is undefined.
A notification string for the
Use this key with the
SCDynamic function. Note that the
Host entity includes the local host name.