Name

Description

VixHandle
VixVM_ReadVariable(VixHandle vmHandle,
                   int variableType,
                   const char *name,
                   int options,
                   VixEventProc *callbackProc,
                   void *clientData);

This function reads variables from the virtual machine state. This includes the virtual machine configuration, environment variables in the guest, and VMware "Guest Variables".

Parameters

vmHandle

Identifies a virtual machine. Call VixVM_Open() to create a virtual machine handle.

variableType

The type of variable to read. The currently supported values are:

• VIX_VM_GUEST_VARIABLE - A "Guest Variable". This is a runtime-only value; it is never stored persistently. This is the same guest variable that is exposed through the VMControl APIs, and is a simple way to pass runtime values in and out of the guest.
• VIX_VM_CONFIG_RUNTIME_ONLY - The configuration state of the virtual machine. This is the .vmx file that is stored on the host. You can read this and it will return the persistent data. If you write to this, it will only be a runtime change, so changes will be lost when the VM powers off.
• VIX_GUEST_ENVIRONMENT_VARIABLE - An environment variable in the guest of the VM. On a Windows NT series guest, writing these values is saved persistently so they are immediately visible to every process. On a Linux or Windows 9X guest, writing these values is not persistent so they are only visible to the VMware tools process.

name

The name of the variable.

options

must be 0.

callbackProc

A callback function that will be invoked when the operation is complete.

clientData

A parameter that will be passed to the callbackProc function.

Return Value

Remarks

• You must call VixVM_LoginInGuest() before calling this function to read a VIX_GUEST_ENVIRONMENT_VARIABLE value. You do not have to call VixVM_LoginInGuest() to use this function to read a VIX_VM_GUEST_VARIABLE or a VIX_VM_CONFIG_RUNTIME_ONLY value.
• The result of the call is in the property VIX_PROPERTY_JOB_RESULT_VM_VARIABLE_STRING on the returning jobHandle.

Side Effects

Requirements

Example

VixError err = VIX_OK;
VixHandle hostHandle = VIX_INVALID_HANDLE;
VixHandle jobHandle = VIX_INVALID_HANDLE;
VixHandle vmHandle = VIX_INVALID_HANDLE;
char *readValue = NULL;

jobHandle = VixHost_Connect(VIX_API_VERSION,
                            VIX_SERVICEPROVIDER_VMWARE_WORKSTATION,
                            NULL, // hostName
                            0, // hostPort
                            NULL, // userName
                            NULL, // password
                            0, // options
                            VIX_INVALID_HANDLE, // propertyListHandle
                            NULL, // callbackProc
                            NULL); // clientData

err = VixJob_Wait(jobHandle,
                  VIX_PROPERTY_JOB_RESULT_HANDLE,
                  &hostHandle,
                  VIX_PROPERTY_NONE);

if (VIX_OK != err) {
   // Handle the error...
   goto abort;
}
Vix_ReleaseHandle(jobHandle);

jobHandle = VixVM_Open(hostHandle,
                       "c:\\Virtual Machines\\vm1\\win2000.vmx",
                       NULL, // callbackProc
                       NULL); // clientData
                       
err = VixJob_Wait(jobHandle,
                  VIX_PROPERTY_JOB_RESULT_HANDLE,
                  &vmHandle,
                  VIX_PROPERTY_NONE);
if (VIX_OK != err) {
   // Handle the error...
   goto abort;
}

Vix_ReleaseHandle(jobHandle);

// Power on the virtual machine before copying file.
jobHandle = VixVM_PowerOn(vmHandle,
                          0, // powerOnOptions
                          VIX_INVALID_HANDLE, // propertyListHandle
                          NULL, // callbackProc
                          NULL); // clientData

err = VixJob_Wait(jobHandle,VIX_PROPERTY_NONE);
if (VIX_OK != err) {
   // Handle the error...
   goto abort;
}

Vix_ReleaseHandle(jobHandle);

// Wait until guest is completely booted.
jobHandle = VixVM_WaitForToolsInGuest(vmHandle,
                                      300, // timeoutInSeconds
                                      NULL, // callbackProc
                                      NULL); // clientData

err = VixJob_Wait(jobHandle, VIX_PROPERTY_NONE);
if (VIX_OK != err) {
   // Handle the error...
   goto abort;
}

Vix_ReleaseHandle(jobHandle);
                               
jobHandle = VixVM_WriteVariable(vmHandle,
                                VIX_VM_GUEST_VARIABLE,
                                "myTestVariable",
                                "newValue",
                                0, // options
                                NULL, // callbackProc
                                NULL); // clientData);
err = VixJob_Wait(jobHandle, VIX_PROPERTY_NONE);
if (VIX_OK != err) {
   // Handle the error...
   goto abort;
}                              
                              
jobHandle = VixVM_ReadVariable(vmHandle,
                               VIX_VM_GUEST_VARIABLE,
                               "myTestVariable",
                               0, // options
                               NULL, // callbackProc
                               NULL); // clientData);
err = VixJob_Wait(jobHandle, 
                  VIX_PROPERTY_JOB_RESULT_VM_VARIABLE_STRING,
                  &readValue,
                  VIX_PROPERTY_NONE);
if (VIX_OK != err) {
   // Handle the error...
   goto abort;
}

abort:
Vix_FreeBuffer(readValue);
Vix_ReleaseHandle(jobHandle);
Vix_ReleaseHandle(vmHandle);
VixHost_Disconnect(hostHandle);