CreateProcess...

David Little -- dlittle@communique.net
Wednesday, September 11, 1996

Environment: VC++ 4.2, Win 95

One of my customers called and said that a program I wrote was "leaving
a white spot everywhere I move it."  I took this to mean that it wasn't
properly painting, but it works fine.  He thinks that I am using
CreateProcess wrong, so somebody tell me:

void CMainFrame::OnRunNotepad() 
{
   STARTUPINFO StartupInfo = {0};
   PROCESS_INFORMATION ProcessInfo;
   StartupInfo.cb = sizeof(STARTUPINFO);

   // blah, blah, blah.....
   CString szCommandLine;
   szCommandLine = "QUICKWINAPP.EXE";

   if (CreateProcess(NULL, szCommandLine, NULL, NULL, FALSE,
          0, NULL, NULL, &StartupInfo, &ProcessInfo))
   {
       WaitForSingleObject(ProcessInfo.hProcess, INFINITE);
          SetCurrentDirectory(savePath);
          ShowWindow(SW_RESTORE);
          EnableWindow(TRUE);
          AfxMessageBox("I finished");
   }
    else
   {
               LPVOID lpMsgBuf;

               FormatMessage(
                       FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
                       NULL,
                       GetLastError(),
                       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                       (LPTSTR) &lpMsgBuf,
                       0,
                       NULL );

                       // Display the string.
                       ::MessageBox( NULL,
                               (LPTSTR)lpMsgBuf,
                               "Create Process",
                               MB_OK|MB_ICONINFORMATION );

                       // Free the buffer.
                  LocalFree( lpMsgBuf );
                  ShowWindow(SW_RESTORE);
                  EnableWindow(TRUE);

	// blah, blah, blah
   }

See any problems?  If you do, let me know...

Thanks!
David

---

Barry Tannenbaum -- barry@dddv.com
Thursday, September 12, 1996

[Mini-digest: 2 responses]

At 12:02 PM 9/11/96 -0500, you wrote:
>Environment: VC++ 4.2, Win 95
>
>One of my customers called and said that a program I wrote was "leaving
>a white spot everywhere I move it."  I took this to mean that it wasn't
>properly painting, but it works fine.  He thinks that I am using
>CreateProcess wrong, so somebody tell me:
>
>void CMainFrame::OnRunNotepad() 
>{
>   STARTUPINFO StartupInfo = {0};
>   PROCESS_INFORMATION ProcessInfo;
>   StartupInfo.cb = sizeof(STARTUPINFO);
>
>   // blah, blah, blah.....
>   CString szCommandLine;
>   szCommandLine = "QUICKWINAPP.EXE";
>
>   if (CreateProcess(NULL, szCommandLine, NULL, NULL, FALSE,
>          0, NULL, NULL, &StartupInfo, &ProcessInfo))
>   {
>       WaitForSingleObject(ProcessInfo.hProcess, INFINITE);
>          SetCurrentDirectory(savePath);
>          ShowWindow(SW_RESTORE);
>          EnableWindow(TRUE);
>          AfxMessageBox("I finished");
>   }
>    else
>   {
>               LPVOID lpMsgBuf;
>
>               FormatMessage(
>                       FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM,
>                       NULL,
>                       GetLastError(),
>                       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
>                       (LPTSTR) &lpMsgBuf,
>                       0,
>                       NULL );
>
>                       // Display the string.
>                       ::MessageBox( NULL,
>                               (LPTSTR)lpMsgBuf,
>                               "Create Process",
>                               MB_OK|MB_ICONINFORMATION );
>
>                       // Free the buffer.
>                  LocalFree( lpMsgBuf );
>                  ShowWindow(SW_RESTORE);
>                  EnableWindow(TRUE);
>
>	// blah, blah, blah
>   }

You're leaking handles for the process and the thread.  Add this just after
the call to WaitForSingleObject:

        ::CloseHandle (ProcessInfo.hProcess);
        ::CloseHandle (ProcessInfo.hThread);

        - Barry

--------------------------------------------------------------------------------

3DV Technology, Inc              Phone: (603) 595-2200 X228
410 Amherst St., Suite 150       Fax:   (603) 595-2228
Nashua, NH  03063                Net:   barry@dddv.com


-----From: Scott Andrew 

The calling application is idle until the applicaion you spawn closes. One
thing that you can do
is stick it in a while loop and call sleep in the loop this should work.

Scott Andrew

---

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