Parallels C API Reference Guide
Obtains the available capabilities of a graceful virtual machine shutdown using Parallels Tools.
PRL_RESULT. Possible values:
PRL_ERR_FAILURE - means that for some reason capabilities of graceful shutdown tool can't be obtained.
PRL_ERR_INVALID_ARG - invalid vm handle or null pointer was passed.
PRL_ERR_UNINITIALIZED - Desktop object is not accessible
PRL_ERR_UNIMPLEMENTED - guest OS shutdown isn't supported
PRL_ERR_SUCCESS - function completed successfully.
When the Parallels Tools package is installed in a virtual machine, a graceful shutdown can be performed from the outside. The available shutdown capabilities depend on the guest operating system and can be obtained using this function.