VIX API Concepts : Objects and Handles

The Vix API is object-based. Most API functions either create objects or operate on the properties of existing objects.

Client applications reference Vix objects with handles. Handles are opaque identifiers (actually integers) that can be passed as parameters to functions. Handles are run-time
only and are unique only within a client's address space.

Most functions in the C-language API take a handle as a parameter. Because a handle value represents an object to the API, this document uses the terms "handle" and "object"
interchangeably.

There are several handle types, but a few of the key types are:

 Virtual Machine -- A single virtual machine, which might or might not be powered on.

 Host -- A single host computer, either the local host or a remote host.

 Job -- An object used in managing asynchronous operations.

 Snapshot -- A snapshot of a virtual machine.

http://www.vmware.com/support/developer/vix-api/vix17_reference/