C# Signature:

[DllImport("kernel32.dll")]
static extern IntPtr OpenProcess(ProcessAccessFlags dwDesiredAccess, [MarshalAs(UnmanagedType.Bool)] bool bInheritHandle, int dwProcessId);

or

[DllImport("kernel32.dll")]
public static extern IntPtr OpenProcess(int dwDesiredAccess, bool bInheritHandle, int dwProcessId);

VB.NET Signature:

<DllImport("kernel32.dll")> _
Private Shared Function OpenProcess(ByVal dwDesiredAccess As ProcessAccessFlags, <MarshalAs(UnmanagedType.Bool)> ByVal bInheritHandle As Boolean, ByVal dwProcessId As Integer) As IntPtr
End Function

Boo Signature:

[DllImport("kernel32")]
static def OpenProcess(dwDesiredAccess as ProcessAccess, bInheritHandle as bool, dwProcessId as int) as IntPtr:
     pass

User-Defined Types:

ProcessAccess

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code (VB.NET):

' Get the handle of a running process
Dim curProcess As Process = Process.GetCurrentProcess()
hProcess = OpenProcess(PROCESS_ACCESS.PROCESS_QUERY_INFORMATION, True, curProcess.Id)

Flags:

[Flags]
enum ProcessAccessFlags : uint
{
    All = 0x001F0FFF,
    Terminate = 0x00000001,
    CreateThread = 0x00000002,
    VMOperation = 0x00000008,
    VMRead = 0x00000010,
    VMWrite = 0x00000020,
    DupHandle = 0x00000040,
    SetInformation = 0x00000200,
    QueryInformation = 0x00000400,
    Synchronize = 0x00100000
}

C# Example

using System;

using System.Runtime.InteropServices;

using System.Text;

public class ShowProcessName

{

    [DllImport("Psapi.dll", SetLastError = true)]
    static extern bool EnumProcesses(
       [MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.U4)] [In][Out] UInt32[] processIds,
     UInt32 arraySizeBytes,
     [MarshalAs(UnmanagedType.U4)] out UInt32 bytesCopied
      );
    [Flags]
    enum ProcessAccessFlags : uint
    {
    All = 0x001F0FFF,
    Terminate = 0x00000001,
    CreateThread = 0x00000002,
    VMOperation = 0x00000008,
    VMRead = 0x00000010,
    VMWrite = 0x00000020,
    DupHandle = 0x00000040,
    SetInformation = 0x00000200,
    QueryInformation = 0x00000400,
    Synchronize = 0x00100000
    }

    [DllImport("psapi.dll")]
    static extern uint GetModuleBaseNameA(IntPtr hProcess, IntPtr hModule, StringBuilder lpBaseName, uint nSize);

    public ShowProcessName()
    {

    UInt32 arraySize = 120;
    UInt32 arrayBytesSize = arraySize * sizeof(UInt32);
    UInt32[] processIds = new UInt32[arraySize];
    UInt32 bytesCopied;

    EnumProcesses(processIds, arrayBytesSize, out bytesCopied);

    for (UInt32 index = 0; index < numIdsCopied; index++)
    {
        Console.WriteLine("ProcessIds[{0}] = {1}", index, processIds[index]);
        IntPtr Handle;
        Handle = OpenProcess(ProcessAccessFlags.QueryInformation | ProcessAccessFlags.VMRead, false, (int)processIds[index]);
        if ((int)Handle <= 4)
        continue;

        StringBuilder BaseName = new StringBuilder();

        GetModuleBaseNameA(Handle, (IntPtr)0, BaseName, 100);

    }

    }

}

Please edit this page!

Do you have...

• helpful tips or sample code to share for using this API in managed code?
• corrections to the existing content?
• variations of the signature you want to share?
• additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).