Re: CreateProcess() it's extermely slow

See below...
On Fri, 03 Aug 2007 09:54:27 -0700, luca.devoti@xxxxxxxxx wrote:

hi all,
I want to create a program that opens all the type of documents
registered on a machine, and the easiest way to do that is to run the
CMD.EXE's START command.
I notice that if my application has no Window, the CreateProcess is
extremely fast as I want. But if I previously create a window (via
CreateWindow()) to run the same command (c:\windows
\system32\cmd.exe /
c start www.google.com) it takes something like 30 secs and it is
hard
to tell what the system is doing.
****
Well, many programs that create windows use MFC, and many programmers link MFC statically,
so there is a truly massive load operation going on. Then if your system has a heavy
paging load, this massive load will cause a lot of page-in and page-out operations. You
have not actually said what you are doing, how many programs you have open at the time,
how much memory you have on your machine, etc.

Note that doing something like running the command processor with a line like

c:\windows\system32\cmd.exe /c "start www.google.com"

is a truly silly way to launch a program. Since you seem to have some concerns about
"efficiency", why are you launching a useless command shell to do the job you want done?
All this does is take up lots of time and memory and serves no known useful purpose.
Instead, use ShellExecute[Ex] with the "open" verb, and eliminate most of the useless
overhead you are now suffering.

It is only in Unix that launching command shells is thought to be a reasonable way of
running programs; in modern operating systems, this is considered a rather quaint way of
doing the job.
joe


Has anyone else reproduced this strange behavior? Do you have any
idea
how to solve that?
thanks in advancing to everyone who will reply
Please let me know if you need the full code to compile, but I think
this snipplet can give an idea
****
Look at ShellExecute, which does what you want without the intermediate overhead.
****


Here is the code I execute


// cWindow.cpp : Defines the entry point for the application.
//


#include "stdafx.h"
#include "cWindow.h"
#define MAX_LOADSTRING 100


// Global Variables:
HINSTANCE
hInst; //
current instance
TCHAR szTitle[MAX_LOADSTRING]; // The
title bar text
TCHAR szWindowClass[MAX_LOADSTRING]; // the main
window class name


// Forward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);


int APIENTRY _tWinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
int nCmdShow)
{
/* if passing "no" as command line I'm calling just execute to
show
that the CreateWindow is alterating
the time spent in CreateProcess */
if (!strcmp(lpCmdLine, "no")){
execute();
exit(0);
}


// TODO: Place code here.
MSG msg;
HACCEL hAccelTable;


// Initialize global strings
LoadString(hInstance, IDS_APP_TITLE, szTitle,
MAX_LOADSTRING);
LoadString(hInstance, IDC_CWINDOW, szWindowClass,
MAX_LOADSTRING);
MyRegisterClass(hInstance);


// Perform application initialization:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}


hAccelTable = LoadAccelerators(hInstance,
(LPCTSTR)IDC_CWINDOW);
execute();
// Main message loop:
while (GetMessage(&msg, NULL, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable,
&msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}


return (int) msg.wParam;



}


//
// FUNCTION: MyRegisterClass()
//
// PURPOSE: Registers the window class.
//
// COMMENTS:
//
// This function and its usage are only necessary if you want this
code
// to be compatible with Win32 systems prior to the
'RegisterClassEx'
// function that was added to Windows 95. It is important to call
this function
// so that the application will get 'well formed' small icons
associated
// with it.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;

wcex.cbSize = sizeof(WNDCLASSEX);


wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = (WNDPROC)WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance,
(LPCTSTR)IDI_CWINDOW);
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = (LPCTSTR)IDC_CWINDOW;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance,
(LPCTSTR)IDI_SMALL);


return RegisterClassEx(&wcex);



}


//
// FUNCTION: InitInstance(HANDLE, int)
//
// PURPOSE: Saves instance handle and creates main window
//
// COMMENTS:
//
// In this function, we save the instance handle in a global
variable and
// create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;

hInst = hInstance; // Store instance handle in our global variable


hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance,
NULL);


if (!hWnd)
{
return FALSE;
}


ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);


return TRUE;



}


//
// FUNCTION: WndProc(HWND, unsigned, WORD, LONG)
//
// PURPOSE: Processes messages for the main window.
//
// WM_COMMAND - process the application menu
// WM_PAINT - Paint the main window
// WM_DESTROY - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc;

switch (message)
{
case WM_COMMAND:
wmId = LOWORD(wParam);
wmEvent = HIWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd,
(DLGPROC)About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam,
lParam);
}
break;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code here...
EndPaint(hWnd, &ps);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;



}


// Message handler for about box.
LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM
lParam)
{
switch (message)
{
case WM_INITDIALOG:
return TRUE;

case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) ==
IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return TRUE;
}
break;
}
return FALSE;



}


int execute(void){

int argc;
_TCHAR* argv[2];
STARTUPINFO si;
PROCESS_INFORMATION pi;
DWORD result;
char lpszMess[50];


/* test data*/
argc=2;
argv[0]="cWindow.exe";
argv[1]="c:\\windows\\system32\\cmd.exe /c start /w www.google.com";


if (argc<2) usage( argc, argv);
ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
ZeroMemory( &pi, sizeof(pi) );


// Start the child process.
if( !CreateProcess( NULL, // No module name (use command line).
argv[1], // Command line.
NULL, // Process handle not inheritable.
NULL, // Thread handle not inheritable.
FALSE, // Set handle inheritance to FALSE.
0, // No creation flags.
NULL, // Use parent's environment block.
NULL, // Use parent's starting directory.
&si, // Pointer to STARTUPINFO structure.
&pi ) // Pointer to PROCESS_INFORMATION
structure.
)
{
result=GetLastError();
/* ZeroMemory( &lpszMess, sizeof(lpszMess) ); */
sprintf(lpszMess,"Errore:%d", result);
MessageBox(NULL,lpszMess, NULL, MB_OK);
return result;
}


// Wait until child process exits.
WaitForSingleObject( pi.hProcess, INFINITE );


// Close process and thread handles.
CloseHandle( pi.hProcess );
CloseHandle( pi.hThread );
if ( argc==3 && !strcmp(argv[2], "debug"))
MessageBox(NULL,"Finito", NULL, MB_OK);


return 0;



}


void usage(int argc, _TCHAR* argv[])
{
char message[100];

ZeroMemory(message, sizeof(message));
sprintf(message, "%s <command name> [debug]", argv[0]);
MessageBox(NULL, message, argv[0], MB_OK);
exit(0);
Joseph M. Newcomer [MVP]
email: newcomer@xxxxxxxxxxxx
Web: http://www.flounder.com
MVP Tips: http://www.flounder.com/mvp_tips.htm
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