About the VM Guest Library
The VM Guest API provides functions that management agents and other software can use to collect data about the state and performance of a VMware virtual machine. The VM Guest API provides fast access to resource management information, without the need for authentication.
The VM Guest API provides read-only access. You can read data using the API, but you cannot send control commands. To send control commands, use the vSphere Web Services SDK. For more information, see the VMware vSphere Web Services SDK Programming Guide and the VMware vSphere API Reference, both of which are available on the VMware developer support Web site.
The VM Guest API version number matches the installed VMware Tools version number.