EDK II代码实例之Variable

    EFI_STATUS      Status        =   EFI_SUCCESS;
    EFI_GUID        OemOSTypeGuid =   {0xd06a0bc7, 0x9feb, 0x4cbb, 0xbd, 0x78, 0xbb, 0xdc, 0xe7, 0x70, 0xef, 0xd3};
    UINT32          Attributes    =   ;
    UINTN           DataSize      =   sizeof (OEM_OS_TYPE2);
    OEM_OS_TYPE2    SaveOSType2;

    Status = pRS->GetVariable (
                         L"VariableName",
                         &OemOSTypeGuid,
                         &Attributes,   // NULL
                         &DataSize,
                         (VOID *)&SaveOSType2  // &SaveOSType2
                         );
    if (EFI_ERROR(Status) && (Status == EFI_NOT_FOUND)) // variable inexistence, then create it
    {
        SaveOSType2.Value = 0x11;

        Status = pRS->SetVariable (
                L"VariableName",
                &OemOSTypeGuid,
                EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, // 0x07
                sizeof (OEM_OS_TYPE2),
                &SaveOSType2
                );
    }