typedef enum _SYSTEM_INFORMATION_CLASS {   
SystemBasicInformation,   
SystemProcessorInformation,   
SystemPerformanceInformation,   
SystemTimeOfDayInformation,   
SystemNotImplemented1,   
SystemProcessesAndThreadsInformation,   
SystemCallCounts,   
SystemConfigurationInformation,   
SystemProcessorTimes,   
SystemGlobalFlag,   
SystemNotImplemented2,   
SystemModuleInformation,   
SystemLockInformation,   
SystemNotImplemented3,   
SystemNotImplemented4,   
SystemNotImplemented5,   
SystemHandleInformation,   
SystemObjectInformation,   
SystemPagefileInformation,   
SystemInstructionEmulationCounts,   
SystemInvalidInfoClass1,   
SystemCacheInformation,   
SystemPoolTagInformation,   
SystemProcessorStatistics,   
SystemDpcInformation,   
SystemNotImplemented6,   
SystemLoadImage,   
SystemUnloadImage,   
SystemTimeAdjustment,   
SystemNotImplemented7,   
SystemNotImplemented8,   
SystemNotImplemented9,   
SystemCrashDumpInformation,   
SystemExceptionInformation,   
SystemCrashDumpStateInformation,   
SystemKernelDebuggerInformation,   
SystemContextSwitchInformation,   
SystemRegistryQuotaInformation,   
SystemLoadAndCallImage,   
SystemPrioritySeparation,   
SystemNotImplemented10,   
SystemNotImplemented11,   
SystemInvalidInfoClass2,   
SystemInvalidInfoClass3,   
SystemTimeZoneInformation,   
SystemLookasideInformation,   
SystemSetTimeSlipEvent,   
SystemCreateSession,   
SystemDeleteSession,   
SystemInvalidInfoClass4,   
SystemRangeStartInformation,   
SystemVerifierInformation,   
SystemAddVerifier,   
SystemSessionProcessesInformation   
} SYSTEM_INFORMATION_CLASS, *PSYSTEM_INFORMATION_CLASS;