Re: Managing Processes

[Aaron Ballman <aaron at realsoftware dot com>]

Moore, Willie wrote:
> I'll see if I can whip something up, assuming that this is what you are
> trying to do.  Just to make sure -- you want to know what process owns
> the frontmost window, just the name of the process or something?
>
> This is exactly what I am trying to do, and any help you can provide would be 
> greatly appreciated.
Here ya go (also added for the next release of the Windows Functionality 
Suite).
Function GetFrontmostWindowHandle() as Integer
  #if TargetWin32
    Declare Function GetForegroundWindow Lib "User32" () as Integer

    return GetForegroundWindow
  #endif
End Function

Function GetActiveProcesses() as ProcessInformation()
  #if TargetWin32
    Declare Function CreateToolhelp32Snapshot Lib "Kernel32" (flags as 
Integer, id as Integer ) as Integer
    Declare Sub CloseHandle Lib "Kernel32" ( handle as Integer )
    Declare Sub Process32First Lib "Kernel32" ( handle as Integer, 
entry as Ptr )
    Declare Function Process32Next Lib "Kernel32" ( handle as Integer, 
entry as Ptr ) as Boolean
    dim snapHandle as Integer
    snapHandle = CreateToolhelp32Snapshot( 2, 0 )

    dim mb as new MemoryBlock( 260 + 36 )
    dim entry as ProcessInformation
    dim ret() as ProcessInformation

    mb.Long( 0 ) = mb.Size
    Process32First( snapHandle, mb )

    dim err as Integer = GetLastError

    do
      entry = new ProcessInformation( mb )

      ret.Append( entry )

      Call Process32Next( snapHandle, mb )
    loop until GetLastError() = 18
    CloseHandle( snapHandle )

    return ret
  #endif
End Function

Function GetFrontmostWindowProcessInformation() as ProcessInformation
  #if TargetWin32
    // We want to get the frontmost window based
    dim frontWindowHWND as Integer
    frontWindowHWND = GetFrontmostWindowHandle

    if frontWindowHWND <= 0 then return nil

    // Now figure out what process ID owns the window
    Declare Sub GetWindowThreadProcessId  Lib "User32" ( hwnd as 
Integer, ByRef procId as Integer )
    dim processID as Integer
    GetWindowThreadProcessId( frontWindowHWND, processId )

    // Now we get a list of all the processes, and see if we can find
    // one with a match.
    dim processes(-1) as ProcessInformation
    processes = GetActiveProcesses

    dim ret as ProcessInformation
    for each ret in processes
      if ret.ProcessID = processID then
        return ret
      end if
    next
  #endif
End Function

And finally, the class ProcessInformation.  Here's the constructor, you 
can figure out the public class properties from it as well.
Constructor( mb as MemoryBlock )
  // Construct one from a memory block

  // First four bytes are the size of the structure, so
  // just ignore them.

  // Four bytes of reference count
  ReferenceCount = mb.Long( 4 )

  // Four bytes of process id
  ProcessID = mb.Long( 8 )

  // Pointer to the default heap id
  if mb.Long( 12 ) <> 0 then
    DefaultHeapID = mb.Ptr( 12 ).Long( 0 )
  end if

  // Module ID
  ModuleID = mb.Long( 16 )

  // Number of threads
  NumberOfThreads = mb.Long( 20 )

  // Parent id
  ParentProcessID = mb.Long( 24 )

  // The base priority for threads
  BaseThreadPriority = mb.Long( 28 )

  // Ignore the next four bytes, they're
  // reserved.

  // And finally, the name
  Name = mb.CString( 36 )
  if Name = "[System Process]" then Name = "System Idle Process"
End Sub

Enjoy!

~Aaron
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