Determining Virtual Machine State

To determine the current state of a virtual machine, first obtain a handle to the virtual machine as described in the Obtaining a List of Virtual Machines section. Then use the PrlVmCfg_GetState function to obtain a handle of type PHT_VM_INFO and call the PrlVmInfo_GetState function to obtain the state information. The function returns the virtual machine state as an enumerator from the VIRTUAL_MACHINE_STATE enumeration that defines every possible state and transition applicable to a virtual machine. The following table lists the available states and transitions:

The following example demonstrates how obtain state/transition information for the specified virtual machine.

PRL_RESULT GetVMstate(PRL_HANDLE hVm)

{

    PRL_HANDLE hJob = PRL_INVALID_HANDLE;

    PRL_HANDLE hJobResult = PRL_INVALID_HANDLE;

    PRL_HANDLE hVmInfo = PRL_INVALID_HANDLE;

    PRL_RESULT ret = PRL_ERR_UNINITIALIZED;

    PRL_RESULT nJobReturnCode = PRL_ERR_UNINITIALIZED;

   // Obtain the PHT_VM_CONFIGURATION handle.

   PRL_HANDLE hVmCfg = PRL_INVALID_HANDLE;

   ret = PrlVm_GetConfig(hVm, &hVmCfg);

    // Obtain a handle of type PHT_VM_INFO containing the

    // state information. The object will also contain the

    // virtual machine access rights info. We will discuss

    // this functionality later in this guide.

    hJob = PrlVm_GetState(hVmCfg);

    // Wait for the job to complete.

    ret = PrlJob_Wait(hJob, 1000);

    if (PRL_FAILED(ret))

    {

        // Handle the error...

        return -1;

    }

    // Analyze the result of PrlVm_GetState.

    ret = PrlJob_GetRetCode(hJob, &nJobReturnCode);

    if (PRL_FAILED(ret))

    {

        // Handle the error...

        PrlHandle_Free(hJob);

        return -1;

    }

    // Check the job return code.

    if (PRL_FAILED(nJobReturnCode))

    {

        // Handle the error...

        PrlHandle_Free(hJob);

        return -1;

    }

    // Get job result.

    ret = PrlJob_GetResult(hJob, &hJobResult);

    PrlHandle_Free(hJob);

    if (PRL_FAILED(ret))

    {

        // Handle the error...

        return -1;

    }

    // Get the PHT_VM_INFO handle.

    ret = PrlResult_GetParam(hJobResult, &hVmInfo);

    PrlHandle_Free(hJobResult);

    if (PRL_FAILED(ret))

    {

        // Handle the error...

        return -1;

    }

    // Get the virtual machine state.

    VIRTUAL_MACHINE_STATE vm_state = VMS_UNKNOWN;

    ret = PrlVmInfo_GetState(hVmInfo, &vm_state);

    if (PRL_FAILED(ret))

    {

        // Handle the error...

        PrlHandle_Free(hVmInfo);

        return -1;

    }

    printf("Status: ");

    switch (vm_state) {

        case VMS_UNKNOWN:

            printf("Unknown state\n");

            break;

        case VMS_STOPPED:

            printf("Stopped\n");

            break;

        case VMS_STARTING:

            printf("Starting...\n");

            break;

        case VMS_RESTORING:

            printf("Restoring...\n");

            break;

        case VMS_RUNNING:

            printf("Running\n");

            break;

        case VMS_PAUSED:

            printf("Paused\n");

            break;

        case VMS_SUSPENDING:

            printf("Suspending...\n");

            break;

        case VMS_STOPPING:

            printf("Stopping...\n");

            break;

        case VMS_COMPACTING:

            printf("Compacting...\n");

            break;

        case VMS_SUSPENDED:

            printf("Suspended\n");

            break;

        default:

            printf("Unknown state\n");

    }

    printf("\n");

    PrlHandle_Free(hVmCfg);    

    PrlHandle_Free(hVmInfo);

    return 0;

}