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;

}