C / C++ / MFC

Re: Can't open more than 16 documents in my application

2-Jan-06 15:04

I am having a rather odd problem with my VC++ application when it comes to opening a certain number of documents. Here's a little background. Each document window that opens is a rather complicated formview run by a rather large and complicated object. The serialization alone saves to a file where the size averages about 200k. when I open around 16 documents, in debug the application pretty much stops working, that is I cannot open anything. Clicking on a menu results in nothing. Clicking the toolbar buttons results in nothing. Navigation completely halts. When run in release the application crashes when i open the 16th document. Sometimes I can get 17.

Now I'm thinking this is a memory issue. Certainly sounds like it. My following questions which I hope someone here can answer are:

1) What do you think this is?
2) If it is memory any ideas on solving it?
3) I was thinking perhaps I could have only the object that is currently active in memory, that is, if a person clicks a document window, then activation that object and clear the rest. Problem here is I have no idea how to do this? Opening up a document takes a bit of time: around 3 to 5 seconds to open a document. If I cleared the object I would have to rebuild it which means a 3 to 5 delay each time we switch to a new document window.
4) Any other ideas?

Thanks for the help! I would include source code, but we are talking a HUGE project here. If you need access to the code I can certainly make that happen. Maybe we can narrow the search down to a few c++ files.

Thanks again!

-- modified at 21:05 Monday 2nd January, 2006

PJ Arends2-Jan-06 15:23

Re: Can't open more than 16 documents in my application

2-Jan-06 15:23

What OS are you using? How much RAM is installed and what is the size of your swap file?

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brdavid3-Jan-06 1:28

Re: Can't open more than 16 documents in my application

3-Jan-06 1:28

Windows XP: Professional, 3GB of RAM installed. Looks like my swap file is 2GB.

PJ Arends3-Jan-06 7:02

Re: Can't open more than 16 documents in my application

3-Jan-06 7:02

With that configuration I doubt very much that you are running out of memory. It could be a resources problem. Have you tried running task manager (taskmgr.exe) while your app is running? Keep an eye on CPU and memory usage, and also watch the number of handles, threads, user objects and GDI objects. If one or more of these get way overused that could be your problem.

brdavid5-Jan-06 4:43

Re: Can't open more than 16 documents in my application

5-Jan-06 4:43

Interesting.... when I reach the 14th or 15th document opened, the CPU usage goes right to 100%. Now it does this everytime a document opens however it goes down once the doc is fully opened. On the 15th doc it stays at 100% which makes sense why I can't run anything else.

I'll start checking a few things. Do you have any ideas yourself?

Thanks for the help thus far! Smile | :)

PJ Arends5-Jan-06 18:28

Re: Can't open more than 16 documents in my application

5-Jan-06 18:28

brdavid wrote:
On the 15th doc it stays at 100%

brdavid wrote:
Do you have any ideas yourself?

Infinite loop.

brdavid6-Jan-06 6:06

accessing non-static variables

6-Jan-06 6:06

okay... I think I'm on to something. Whenever I open a new document the cpu usage peaks, but then doesn't return back to a low number. In fact with each new doc the low value increases until I reach a 100%. Now apparently I can still open up documents but I have a feeling at some point I just hit the limit with whatever is eating up the CPU. I started eliminating logic from the main window, which are tabs with formviews until I got down to one tab. The application now opens up more documents than before and the CPU usage goes back down to under 5 and sometimes zero. So somewhere in my logic for the tabs I have in my main window is causing the problem. I'll give more information when I have it finally nailed.

Thanks for the help. Smile | :)

edit: I have isolated the issue, which makes this even more weird. It has to do with this call:

<br />
	pList->CreateEx(WS_EX_CLIENTEDGE, dwStyle, rect, this, IDC_ITEMLISTCONTROL);<br />

Here's the weird part. I set up the application so that I can control the number of times this value is called per document. If called once per document the cpu usage starts to increase the more documents I open until it peaks at 100%. This happens in a custom list ctrl. I have another control that uses the same CreateEx method that subclasses ListCtrl as well and I do not have this issue, so somewhere in this MyListCtrl is the issue which happens to be related to CreateEx().

Weird. Confused | :confused:

edit: update:

<br />
int CMyListCtrl::OnCreate(LPCREATESTRUCT lpCreateStruct)<br />
{<br />
	CListCtrl::OnCreate(lpCreateStruct);<br />
	//if (CListCtrl::OnCreate(lpCreateStruct) == -1)<br />
	//{<br />
	//	ASSERT(FALSE);<br />
		return -1;<br />
	//}<br />
<br />
	// When the CMyListCtrl object is created via a call to Create(), instead<br />
	// of via a dialog box template, we must subclass the header control<br />
	// window here because it does not exist when the PreSubclassWindow()<br />
	// function is called.<br />
<br />
	//SubclassHeaderControl();<br />
	//return 0;<br />
}<br />

in turning the OnCreate method into this the CPU usage stays low. When I return 0 like it should the CPU starts to increase upwards the more docs I add. This is becoming a rather difficult problem. Cry | :((

-- modified at 18:45 Friday 6th January, 2006

tonyro2-Jan-06 13:37

tonyro

2-Jan-06 13:37

I'm trying to access a variable (this->number) from a separate function in a different file. Is there an easy way to do this, like using a global variable or passing the value between functions as one would in C? When I try to access the variable with namespace::functionname::variable, I get the following error message: error C2597: illegal reference to non-static member 'namespace::functionname::variable'. Any help would be greatly appreciated!

Re: accessing non-static variables

PJ Arends2-Jan-06 15:09

2-Jan-06 15:09

Have you looked up C2597 in MSDN[^]?
[quote]
To access the nonstatic member, you must create an instance of the class and use a member-access operator (. or ->).
[/quote]

FlashWindowEx

Dody_DK2-Jan-06 10:55

Dody_DK

2-Jan-06 10:55

Why I can't use the FlashWindowEx() with MFC based dialog...

it gives me that FlashWindowEx is not declared, any way to use it?

thanks in advance...

PJ Arends2-Jan-06 15:15

2-Jan-06 15:15

FlashWindowEx is declared in WinUser.h. If you open WinUser.h and do a text search for FlashWindowEx you will see that FlashWindowEx is wrapped in a pre-processor conditional statement "#if(WINVER >= 0x0500)". So to use FlashWindowEx you have to #define WINVER 0x0500 at the top of your stdafx.h file.

Dody_DK2-Jan-06 23:39

Dody_DK

2-Jan-06 23:39

the problem is I don't have FlashWindowEx in the WinUser.h

here is what I have

FlashWindow(<br />
    HWND hWnd,<br />
#if(WINVER >= 0x0500)<br />
    DWORD dwFlags);<br />
#else<br />
    BOOL bInvert);<br />
#endif<br />
<br />
#if(WINVER >= 0x0500)<br />
#define FLASHW_STOP         0<br />
#define FLASHW_CAPTION      0x00000001<br />
#define FLASHW_TRAY         0x00000002<br />
#define FLASHW_ALL          (FLASHW_CAPTION | FLASHW_TRAY)<br />
#define FLASHW_TIMER        0x00000004<br />
#define FLASHW_TIMERNOFG    0x0000000C<br />
#endif /* WINVER >= 0x0500 */

any help with it? thanks....

Gavin Taylor3-Jan-06 6:32

Gavin Taylor

3-Jan-06 6:32

You've probobly still got a REALLY old version of the platform SDK, you've got two options, either download[^] the latest version or access the FlashWindowEx function on the fly using GetProcAddress[^].

If you choose the later option, you'll need something like:

/* Taken from the MSDN website*/
typedef struct {
    UINT  cbSize;
    HWND  hwnd;
    DWORD dwFlags;
    UINT  uCount;
    DWORD dwTimeout;
} FLASHEXINFO, *PFLASHEXINFO;
	
#define FLASHW_STOP         0
#define FLASHW_CAPTION      0x00000001
#define FLASHW_TRAY         0x00000002
#define FLASHW_ALL          (FLASHW_CAPTION | FLASHW_TRAY)
#define FLASHW_TIMER        0x00000004
#define FLASHW_TIMERNOFG    0x0000000C
	
typedef BOOL (WINAPI *PSFLEX)(PFLASHEXINFO);
	
	
static PSFLEX pFlashWindowEx = NULL; // Pointer to actual function
static BOOL initFlash = FALSE; // Loaded status
	
BOOL uiFlashWindowEx( HWND hWnd, UINT uCount /* Flash Count */, DWORD dwFlags /* check SDK */ )
{
	if ( ! initFlash )
	{ // Not loaded yet
		HMODULE hDLL = NULL;
		hDLL = LoadLibrary( TEXT( "user32.dll" ) );
		if( hDLL )
		{
			pFlashWindowEx  = ( PSFLEX ) GetProcAddress( hDLL, "FlashWindowEx" );
			initFlash = TRUE; // Loaded OK
		}
	}
	
	if ( pFlashWindowEx == NULL ) 
		return FALSE; // Not Supported
	
	FLASHEXINFO fwi;
	ZeroMemory( & fwi, sizeof( FLASHEXINFO ) );
	fwi.cbSize = sizeof( FLASHEXINFO );
	fwi.dwFlags = dwFlags;
	fwi.hwnd = hWnd;
	fwi.uCount = uCount;
	fwi.dwTimeout = 0L;
	return pFlashWindowEx ( & fwi );
}

Once done, just use uiFlashWindowEx( hWnd, 3, FLASHW_TRAY ); or whatever

Gavin Taylor
w: http://www.gavspace.com

-- modified at 12:37 Tuesday 3rd January, 2006