Examine Information on Windows NT System Level Primitives

Tuesday Nov 14th 2000 by Zoltan Csizmadia

Two low level utilities to examine Windows NT information such as processes, threads, windows, modules and objects.

Environment: Windows NT 4.0/2000 only, VC6 SP4, NT DDK is not needed :)


This article presents two separate utilities (NtSysInfo and WhoUses) to examine low level information on such Windows NT system primitives such as processes, threads, windows, modules and objects. Some of the things that I'm doing here are similar to the utilities found on the sysinternals Web site.

NtSysInfo Syntax

NtSysInfo enables you to explore the Windows NT internals and enumerate the system's processes, windows, threads, objects.
Usage: NtSysInfo.exe [/H[type]|/M[dllname]|/P|/T|/W] [processId]}
 /H          Handle list. Can be filtered by "type"
             type: File, Thread, Semaphore, Process, Event,...
 /M          Module list. Can be filtered by "dllname"
 /P          Process list (processId not used)
 /T          Thread list
 /W          Window list
 processId   Process ID, dec. or 0x??? (-1 = every process, default)

  NtSysInfo.exe /HFile 651
  NtSysInfo.exe /H 1248
  NtSysInfo.exe /Mkernel32.dll
  NtSysInfo.exe /P
  NtSysInfo.exe /W
  NtSysInfo.exe /W 1215

WhoUses Syntax

NtSysInfo allows you to list processes, windows, threads, objects. The WhoUses utility enalbes you to determine what process has a file or DLL locked.
Usage: WhoUses.exe [/M] fileName
  /M         fileName is a module name ( EXE, DLL, ... )
  fileName   File name

  WhoUses.exe /M kernel32.dll
  WhoUses.exe /M c:\test\test.dll
  WhoUses.exe yourTextFile.txt
  WhoUses.exe c:\pagefile.sys
  WhoUses.exe Serial0

Code Examples

  1. Get the process list
  2. SystemProcessInformation pi;
    // Iterate through pi.m_ProcessInfos
  3. Get the thread list
  4. // processId == -1 means every process
    SystemThreadInformation ti( processId ); 
    // Iterate through ti.m_ThreadInfos
  5. Get the object list
  6. // processId == -1 means every process
    SystemHandleInformation oi( processId ); 
    // Iterate through oi.m_HandleInfos
  7. Get the file object list
  8. // processId == -1 means every process
    SystemHandleInformation fi( processId ); 
    fi.SetFilter( _T("File"), TRUE ); // Refresh
    // Iterate through fi.m_HandleInfos
  9. Get the window list
  10. // processId == -1 means every process
    SystemWindowInformation wi( processId ); 
    // Iterate through wi.m_WindowInfos
  11. Get window list
  12. // processId == -1 means every process
    SystemModuleInformation mi( processId ); 
    // Iterate through mi.m_ModuleInfos

Warnings & Disclaimers

This software uses a few undocumented functions (ntdll.dll), peeks around in your systems internals. Use at your own risk! It works for me. :)


  • Book: Undocumented Windows NT by Prasad Dabak, Sandeep Phadke, Milind Borate
  • Book: Windows NT/2000 Native API Reference by Gary Nebbett
  • Web: System Internals, www.sysinternals.com


Download source/demo code - 38 Kb
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