# Creating a process, and then killing it

, 22 Nov 1999
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Creating a process, and then killing it.

## Introduction

While I was creating an app that has the capability of starting a process, and then be able to kill it later on, I looked all over the net, and found some crazy ways of doing this. Searching, searching, searching, for a couple days, I did nothing but try to locate info on setting this up correctly (Since I never tried doing this before). Most of them I could not get to work, in their entirety, as they were written. I finally found a way that worked, without too much mish-mash. What is here, is a conglomerate of all. And needless to say, the simplest way was the key. I am sure there are better ways of doing this, but this way works for this application.

Please note that some of the techniques used in this article are based on the article Sending a message to the Main Frame Window of Another Application, given only the Process Handle by Martin-Pierre Frenette.

The basic method used is to start a process, store its process ID, and then when it comes time to kill the process, you enumerate all open windows and close the window that is associated with your process ID.

TerminateProcess() is easier, but doesn't unload the DLLs from memory, which means it doesn't let the DLLs know the process is terminated, and leaves them floating around in memory, lost, causing problems. It should only be used in worst-case situations. system(), WinExec(), ShellExecute(), and ShellExecueEx() are easier, but you don't get as much information about the process being started. Since CreateProcess() is very powerful, and seems rather intimidating at first, I decided to write this little article.

PostMessage() needs a window handle to send WM_CLOSE, so we have to use EnumWindows() to ramble through the windows, checking to see if our PID is the same. If it is, we have a match, and have the window handle to send it.

### In CSomeDlg.h

static BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam);
DWORD processPid;

### In CSomeDlg.cpp

void CSomeDlg::startProcess()
{
BOOL bWorked;
STARTUPINFO suInfo;
PROCESS_INFORMATION procInfo;
CString m_Process = "C:\\wherever\\process\\we\\want\\to\\start.exe";
char *vip =  "C:\\wherever\\process\\we\\want\\to\\start.exe "
"whatever command line arguments here";

memset (&suInfo, 0, sizeof(suInfo));
suInfo.cb = sizeof(suInfo);

bWorked = ::CreateProcess(m_Process,
vip,      // can also be NULL
NULL,
NULL,
FALSE,
NORMAL_PRIORITY_CLASS,
NULL,
NULL,
&suInfo,
&procInfo);

/*
procInfo has these members
HANDLE hProcess;   // process handle
DWORD dwProcessId; // process PID
*/

if (procInfo.dwThreadId = NULL)
{
MessageBox("nope");
}

playerPid = procInfo.dwProcessId;
}

void CSomeDlg::killProcess()
{
HANDLE ps = OpenProcess( SYNCHRONIZE|PROCESS_TERMINATE,
FALSE, processPid);
// processPid = procInfo.dwProcessId;

// This function enumerates all widows,
// using the EnumWindowsProc callback
// function, passing the PID of the process
// you started earlier.
EnumWindows(EnumWindowsProc, processPid);

CloseHandle(ps) ;
}

BOOL CALLBACK CSomeDlg::EnumWindowsProc(HWND hwnd, LPARAM lParam)
{
DWORD wndPid;
CString Title;
// lParam = procInfo.dwProcessId;

// This gets the windows handle and pid of enumerated window.

// This gets the windows title text
// from the window, using the window handle
CWnd::FromHandle( hwnd )->GetWindowText(Title);

//  this makes sure that the PID matches that PID we started, and window
// text exists, before we kill it . I don't think this is really needed,
// I included it because some apps have more than one window.
if ( wndPid == (DWORD)lParam && Title.GetLength() != 0)
{
//  Please kindly close this process
::PostMessage(hwnd, WM_CLOSE, 0, 0);
return false;
}
else
{
// Keep enumerating
return true;
}
}

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

## About the Author

Software Developer Nokia Pty Ltd
Australia
No Biography provided

## Comments and Discussions

 First Prev Next
 process creation Member 4250705 23-Dec-08 0:29
 process prathuraj 9-Apr-07 1:04
 Process in a Thread Gagan komal 16-Nov-06 22:20
 Great help ellasunxl 13-Jun-06 17:20
 Re: Great help tifen 27-Jul-09 18:22
 Problem in retreving the HANDLE of the window Raj2411 29-Mar-06 0:12
 Application? Rodolfo Brazil 29-Mar-05 7:09
 Linking error NTSC 12-Nov-03 14:20
 Re: Linking error Agus Subhan Akbar 26-May-05 21:40
 Passing instruction to the screen vgandhi 13-Aug-03 14:42
 a simple question I hope Gregor Schiller 1-Feb-03 10:14
 Re: a simple question I hope ljp 1-Feb-03 10:35
 Using this in Visual c++? microcyb 26-Dec-02 7:27
 Re: Using this in Visual c++? Anonymous 7-Aug-03 4:01
 hProcess.. Preetham 26-Apr-02 15:01
 Re: hProcess.. Anonymous 2-May-02 17:28
 Not working? Conphused1 9-Mar-02 13:11
 Re: Not working? Rob maddison 27-Jan-03 3:51
 playerPid = procInfo.dwProcessId; virle 23-Feb-02 20:17
 Re: playerPid = procInfo.dwProcessId; kidconan 11-Aug-05 21:45
 how Can I start "service program"? Ahnse 28-Jun-01 18:04
 Re: how Can I start "service program"? cjc 2-May-02 17:30
 Error Gunter Blasek 15-May-01 4:34
 Killing a process H.K. Subbu 7-Aug-00 22:11
 A much different direction. nerddude 18-Oct-03 20:38
 Last Visit: 31-Dec-99 19:00     Last Update: 2-Mar-15 5:22 Refresh 1

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