QUERY_VIRTUAL_MEMORY_CALLBACK - NtDoc

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

typedef NTSTATUS QUERY_VIRTUAL_MEMORY_CALLBACK(
    _Inout_ HANDLE CallbackContext,
    _In_ HANDLE ProcessHandle,
    _In_opt_ PVOID BaseAddress,
    _In_ HEAP_MEMORY_INFO_CLASS MemoryInformationClass,
    _Out_writes_bytes_(MemoryInformationLength) PVOID MemoryInformation,
    _In_ SIZE_T MemoryInformationLength,
    _Out_opt_ PSIZE_T ReturnLength
    );

#endif

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This callback function is documented in Windows Driver Kit.