SYSTEM_POWER_STATE_CONTEXT - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTPOAPI_H

// wdm
typedef struct _SYSTEM_POWER_STATE_CONTEXT
{
    union
    {
        struct
        {
            ULONG Reserved1 : 8;
            ULONG TargetSystemState : 4;
            ULONG EffectiveSystemState : 4;
            ULONG CurrentSystemState : 4;
            ULONG IgnoreHibernationPath : 1;
            ULONG PseudoTransition : 1;
            ULONG KernelSoftReboot : 1;
            ULONG DirectedDripsTransition : 1;
            ULONG Reserved2 : 8;
        };
        ULONG ContextAsUlong;
    };
} SYSTEM_POWER_STATE_CONTEXT, *PSYSTEM_POWER_STATE_CONTEXT;

#endif

View code on GitHub

This structure is documented in Windows Driver Kit here and here.