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Full-Featured Task Manager for Windows Mobile

, 17 Feb 2008
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A full-featured Task Manager for Windows Mobile.

Introduction

There are many task managers for Windows Mobile out there, but I've never seen one that shows how much memory is being used by each process. I found this odd until I started digging into why. Microsoft hasn't provided the standard APIs for querying for a process' memory usage because memory works differently on WM. Fortunately, they did provide the Toolhelp32 APIs. This article implements a Task Manager for Windows Mobile that utilizes the Toolhelp32 library to take a snapshot of the heap and tally the memory usage for every process.

Background

The company I work for recently implemented a new mobile email solution. I found my phone/PPC's memory was frequently around 1MB even though the Task Manager that comes with WM didn't list any running processes. I decided to write a quick utility to walk active processes, and found the built-in task manager was only displaying processes which had a main window. I turned that utility into version 0.5 which displayed all processes, let me kill them, etc. I still hadn't answered my question about which process was chewing up my memory and if it was associated with the new email solution. I was frustrated by the lack of APIs for finding memory usage statistics. I needed to know how much memory the processes associated with my company's email solution was using, so I dug deeper. What I've published here is my final solution.

Using the Code

I won't spend much time describing how the application as a whole works, it's pretty standard. There is a file named Toolhelp32.cs which contains all the P/Invoke signatures needed to use the Toolhelp32 library. Below is the block of code that does the grunt work.

uint GetMemUsage(uint ProcId)
{
  uint MemUsage = 0;
  IntPtr hHeapSnapshot = 
   Toolhelp32.CreateToolhelp32Snapshot(Toolhelp32.TH32CS_SNAPHEAPLIST, ProcId);
  if (hHeapSnapshot != INVALID_HANDLE_VALUE)
  {
    Toolhelp32.HEAPLIST32 HeapList = new Toolhelp32.HEAPLIST32();
    HeapList.dwSize = (uint)Marshal.SizeOf(HeapList);
    if (Toolhelp32.Heap32ListFirst(hHeapSnapshot, ref HeapList))
    {
      do 
      {
        Toolhelp32.HEAPENTRY32 HeapEntry = new Toolhelp32.HEAPENTRY32();
        HeapEntry.dwSize = (uint)Marshal.SizeOf(HeapEntry);
        if (Toolhelp32.Heap32First(hHeapSnapshot, ref HeapEntry, 
                    HeapList.th32ProcessID, HeapList.th32HeapID))
        {
          do
          {
            MemUsage += HeapEntry.dwBlockSize;
          } while (Toolhelp32.Heap32Next(hHeapSnapshot, ref HeapEntry));
        }
      } while (Toolhelp32.Heap32ListNext(hHeapSnapshot, ref HeapList));
    } 
    Toolhelp32.CloseToolhelp32Snapshot(hHeapSnapshot);
  }
  return MemUsage;
}

CreateToolhelp32Snapshot creates a snapshot of processes, threads, heaps, and modules of a process. I pass in the TH32CS_SNAPHEAPLIST, telling it I want information about the heap list. Once I have the snapshot, I walk the heaplists with the Heap32ListFirst and Heap32ListNext calls. For each list, I walk the heap with Heap32First and Heap32Next, and add up the block sizes for each entry in each list. Voila, the total allocated blocks for a process.

Points of Interest

There are lots of great articles out there on memory management for WM. I wish I had saved them so I could post the links here. All I can say is memory management on WM, while not nearly as robust as for a desktop OS, is much more complicated. Read-up before attempting anything more than Hello World for WM. And yes, the new email solution was the culprit.

History

  • Initial version posted 02/14/2008 8:50PM (EST).

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Brian P. Adams

United States United States
No Biography provided

Comments and Discussions

 
QuestionReal memory usage ? Pinmembersir_zealot@go2.pl19-Aug-09 3:12 
QuestionKill a process ?? PinmemberGamePlanner17-Jul-09 5:57 
GeneralError PinmemberPavanPareta22-Nov-08 0:07 
GeneralRe: Error PinmemberBrian P. Adams1-Jun-09 6:19 
GeneralRe: regarding code PinmemberMarijn Stevens10-Jul-08 13:39 
GeneralBuilding the project with VS2005 and removing OpenNETCF PinmemberJeoff Hines15-May-08 2:55 
GeneralRe: Building the project with VS2005 and removing OpenNETCF PinmemberGary Dobbins6-Jun-08 4:54 
GeneralRe: Building the project with VS2005 and removing OpenNETCF PinmemberJeoff Hines9-Jun-08 3:13 
GeneralVS2005 version Pinmemberfbausch10-Mar-08 6:10 
GeneralNice one Pinmembergore0118-Feb-08 0:22 

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