pub const PEB = extern struct {
    // Versions: All
    InheritedAddressSpace: BOOLEAN,

    // Versions: 3.51+
    ReadImageFileExecOptions: BOOLEAN,
    BeingDebugged: BOOLEAN,

    // Versions: 5.2+ (previously was padding)
    BitField: UCHAR,

    // Versions: all
    Mutant: HANDLE,
    ImageBaseAddress: HMODULE,
    Ldr: *PEB_LDR_DATA,
    ProcessParameters: *RTL_USER_PROCESS_PARAMETERS,
    SubSystemData: PVOID,
    ProcessHeap: HANDLE,

    // Versions: 5.1+
    FastPebLock: *RTL_CRITICAL_SECTION,

    // Versions: 5.2+
    AtlThunkSListPtr: PVOID,
    IFEOKey: PVOID,

    // Versions: 6.0+

    /// https://www.geoffchappell.com/studies/windows/win32/ntdll/structs/peb/crossprocessflags.htm
    CrossProcessFlags: ULONG,

    // Versions: 6.0+
    union1: extern union {
        KernelCallbackTable: PVOID,
        UserSharedInfoPtr: PVOID,
    },

    // Versions: 5.1+
    SystemReserved: ULONG,

    // Versions: 5.1, (not 5.2, not 6.0), 6.1+
    AtlThunkSListPtr32: ULONG,

    // Versions: 6.1+
    ApiSetMap: PVOID,

    // Versions: all
    TlsExpansionCounter: ULONG,
    // note: there is padding here on 64 bit
    TlsBitmap: *RTL_BITMAP,
    TlsBitmapBits: [2]ULONG,
    ReadOnlySharedMemoryBase: PVOID,

    // Versions: 1703+
    SharedData: PVOID,

    // Versions: all
    ReadOnlyStaticServerData: *PVOID,
    AnsiCodePageData: PVOID,
    OemCodePageData: PVOID,
    UnicodeCaseTableData: PVOID,

    // Versions: 3.51+
    NumberOfProcessors: ULONG,
    NtGlobalFlag: ULONG,

    // Versions: all
    CriticalSectionTimeout: LARGE_INTEGER,

    // End of Original PEB size

    // Fields appended in 3.51:
    HeapSegmentReserve: ULONG_PTR,
    HeapSegmentCommit: ULONG_PTR,
    HeapDeCommitTotalFreeThreshold: ULONG_PTR,
    HeapDeCommitFreeBlockThreshold: ULONG_PTR,
    NumberOfHeaps: ULONG,
    MaximumNumberOfHeaps: ULONG,
    ProcessHeaps: *PVOID,

    // Fields appended in 4.0:
    GdiSharedHandleTable: PVOID,
    ProcessStarterHelper: PVOID,
    GdiDCAttributeList: ULONG,
    // note: there is padding here on 64 bit
    LoaderLock: *RTL_CRITICAL_SECTION,
    OSMajorVersion: ULONG,
    OSMinorVersion: ULONG,
    OSBuildNumber: USHORT,
    OSCSDVersion: USHORT,
    OSPlatformId: ULONG,
    ImageSubSystem: ULONG,
    ImageSubSystemMajorVersion: ULONG,
    ImageSubSystemMinorVersion: ULONG,
    // note: there is padding here on 64 bit
    ActiveProcessAffinityMask: KAFFINITY,
    GdiHandleBuffer: [
        switch (@sizeOf(usize)) {
            4 => 0x22,
            8 => 0x3C,
            else => unreachable,
        }
    ]ULONG,

    // Fields appended in 5.0 (Windows 2000):
    PostProcessInitRoutine: PVOID,
    TlsExpansionBitmap: *RTL_BITMAP,
    TlsExpansionBitmapBits: [32]ULONG,
    SessionId: ULONG,
    // note: there is padding here on 64 bit
    // Versions: 5.1+
    AppCompatFlags: ULARGE_INTEGER,
    AppCompatFlagsUser: ULARGE_INTEGER,
    ShimData: PVOID,
    // Versions: 5.0+
    AppCompatInfo: PVOID,
    CSDVersion: UNICODE_STRING,

    // Fields appended in 5.1 (Windows XP):
    ActivationContextData: *const ACTIVATION_CONTEXT_DATA,
    ProcessAssemblyStorageMap: *ASSEMBLY_STORAGE_MAP,
    SystemDefaultActivationData: *const ACTIVATION_CONTEXT_DATA,
    SystemAssemblyStorageMap: *ASSEMBLY_STORAGE_MAP,
    MinimumStackCommit: ULONG_PTR,

    // Fields appended in 5.2 (Windows Server 2003):
    FlsCallback: *FLS_CALLBACK_INFO,
    FlsListHead: LIST_ENTRY,
    FlsBitmap: *RTL_BITMAP,
    FlsBitmapBits: [4]ULONG,
    FlsHighIndex: ULONG,

    // Fields appended in 6.0 (Windows Vista):
    WerRegistrationData: PVOID,
    WerShipAssertPtr: PVOID,

    // Fields appended in 6.1 (Windows 7):
    pUnused: PVOID, // previously pContextData
    pImageHeaderHash: PVOID,

    /// TODO: https://www.geoffchappell.com/studies/windows/win32/ntdll/structs/peb/tracingflags.htm
    TracingFlags: ULONG,

    // Fields appended in 6.2 (Windows 8):
    CsrServerReadOnlySharedMemoryBase: ULONGLONG,

    // Fields appended in 1511:
    TppWorkerpListLock: ULONG,
    TppWorkerpList: LIST_ENTRY,
    WaitOnAddressHashTable: [0x80]PVOID,

    // Fields appended in 1709:
    TelemetryCoverageHeader: PVOID,
    CloudFileFlags: ULONG,
}