Problem with auto_ptr !!! - C / C++ / MFC Discussion Boards

Re: Help File

act_x6-Dec-02 9:43

act_x

6-Dec-02 9:43

Thanks for the help but unfortunately I am getting a Linker error saying

Linking...<br />
MainFrm.obj : error LNK2001: unresolved external symbol _HtmlHelpA@16<br />
Debug/MDI2.exe : fatal error LNK1120: 1 unresolved externals<br />
Error executing link.exe.<br />
<br />
MDI2.exe - 2 error(s), 0 warning(s)

I copied the htmlhelp.h file to the VC98 include directory
and copied the htmlhtlp.lib file to th eVC98 lib directory.
Also I my .cpp I included like #include "htmlhelp.h"

What am I Doing wrong ? Please help

Re: Help File

Paul M Watt6-Dec-02 10:27

Paul M Watt

6-Dec-02 10:27

did you reference the HTMLHEML.lib file in your projects link settings? You need to actually reference the lib in your project, otherwise the linker will not know that it needs to link that file in.

Hit Alt + F7 then go to the link tab. In the "Object/Library Modules" edit field add HTMLHelp.lib and that should fix your problems.

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Thank you all

act_x6-Dec-02 10:39

act_x

6-Dec-02 10:39

Thanks a lot for the suggestions . I was able to invoke a File. THanks

Re: Help File

Gaul7-Dec-02 19:14

Gaul

7-Dec-02 19:14

What do you recommend for creating/editing the help file text/source?

Gaulles

Re: Help File

lucy9-Dec-02 2:21

lucy

9-Dec-02 2:21

I am using HTMLHelp Workshop. You can download it from Microsoft's web site.

HWND to a UIThread

David_Leikis6-Dec-02 8:35

David_Leikis

6-Dec-02 8:35

I am trying to create a thread to monitor a USB-connected ADC module. Its driver uses a callback function for the configuration of the module. It requires a CWnd handle given to it such that when it has a buffer filled, it sends a OLDA_WM_BUFFER_DONE message to the thread. I created a UIThread so that it would have a message handler and I could create my OnBufferDone function. (Which is working and tested in a single thread situation.) It needs to be in a separate thread so that I can empty the buffer quickly
and move the sample data into my internal buffers and return it back to the ADC module driver before the next buffer_full message comes in.

Does anyone know how to create or get a HWND for a UIThread so that this driver can know where to send messages to my thread?

Thanks in advance,
Dave
Cry | :((

Re: HWND to a UIThread

KaЯl7-Dec-02 1:59

KaЯl

7-Dec-02 1:59

Have you had a look to PostThreadMessage[^] ?

HTH,

K.

I hurt so bad inside
I wish you could see the world through my eyes
It stays the same
I just wanna laugh again

Problem with auto_ptr !!!

Luc Bergeron6-Dec-02 8:30

Luc Bergeron

6-Dec-02 8:30

Hello to all.

I've checked this following article (http://www.cuj.com/experts/1906/hyslop.htm?topic=experts) at CUJ web site and decided to use it in my own application.

So here we go. I have managed to implement the factory inside a windows DLL. But i'm having weird problems with it. Mainly the genericFactory::create method.

This is how i've implemented it (with the modification that I use a pointer to a function with three std::string parameters) :
template <class manufacturedobj,="" typename="" classidkey="">
std::auto_ptr<manufacturedobj>
genericFactory<manufacturedobj, classidkey="">::create(const classIDKey &className,
const std::string& p1,
const std::string& p2,
const std::string& p3) const
{
std::auto_ptr<manufacturedobj> ret(0);
FN_REGISTRY::const_iterator regEntry=registry.find(className);
if (regEntry != registry.end())
{
ret = regEntry->second(p1, p2, p3);
}

return ret;
}

And in my client code this is how I call it :
std::auto_ptr<mysqltable> tbl(0);
tbl = genericFactory<mysqltable>::instance().create("HistoricalDataTbl", host, user, pwd);
-----------------------------------------------------------------------------------------------

When I trace inside the create method, the "ret" variable is fine and points to a valid MySQLTable object. BUT, when the function returns to the client code... I get an unhandled exception error. This error is generated inside the auto_ptr<>::reset() method. To be more precise, the "tbl" auto_ptr in the client code is supposed to be initialized with a NULL pointer but when getting back from genericFactory::create method the "tbl" pointer points to an invalid MySQLTable object.

The quilty code inside auto_ptr :
void reset(_Tp* __px=0) {
_Tp* __pt = this->get();
if (__px != __pt)
delete __pt; //offending line...
this->__set(__px);
}

So i'm currently puzzled has to why the "tbl" variable points to a bad MySQLTable object!?!?!?!

Any help would be greatly appreciated Big Grin | :-D

Luc.

Re: Problem with auto_ptr !!!

Alvaro Mendez6-Dec-02 9:50

Alvaro Mendez

6-Dec-02 9:50

Well, your sample code doesn't look good since the template parameters were lost by the HTML translation. Try putting the code inside pre tags next time.

However, I did take a quick peek it and it seems like the problem is with your regEntry variable. It's a local variable which, I assume, is returning to you a pointer to a MySQLTable object via the second function which it created internally. My guess is that when the create function returns, regEntry goes away and so does the MySQLTable pointer that it was holding -- which is also in your ret variable. So ret is left holding on to a pointer which is no longer valid.

That's one guess, based on my complete lack of knowledge on FN_REGISTRY.

Another guess is that it has to do with how ret variable is being copied and freed when it gets returned. But it shouldn't be that since ret would be "released" before being copied to tbl, and then it would be freed with a NULL pointer -- should be no problem.

BTW, I noticed you're not using Microsoft's auto_ptr implementation, which doesn't even have a reset (at least not the one in VC6.0)

Regards,
Alvaro

Well done is better than well said. -- Benjamin Franklin
(I actually prefer medium-well.)

Re: Problem with auto_ptr !!!

Luc Bergeron6-Dec-02 10:01

Luc Bergeron

6-Dec-02 10:01

Here is how FN_REGISTRY is defined...

typedef std::auto_ptr<manufacturedObj> (*BASE_CREATE_FN)(const std::string&,
                                                         const std::string&,
                                                         const std::string&);

// FN_REGISTRY is the registry of all the BASE_CREATE_FN
// pointers registered.  Functions are registered using the
// regCreateFn member function (see below).
typedef std::map<classIDKey, BASE_CREATE_FN> FN_REGISTRY;
FN_REGISTRY registry;

And I use STLPort !!!

P.S. How come, after using the pre tags, that my "<" and ">" gets deleted !?!?!?

Dynamic CEdit can't call DoDataExchange()?

dazinith6-Dec-02 8:20

dazinith

6-Dec-02 8:20

Hey there.. ive never created CEdits without the dialog editor.. now i am trying to create a bunch and have DoDataExchange() when they lose focus.. it doesn't look like DoDataExchange ever gets called in my view tho.. here is how i am creating my fields:

CEdit* pEdit = new CEdit;
pEdit->Create(WS_CHILD | WS_VISIBLE | WS_TABSTOP | WS_BORDER | ES_AUTOHSCROLL,
    CRect(10, 10, 110, 30), this, 1);

how can i make a field like this call DoDataExchange() when it gains focus? or better yet, how can i make it call a function when it loses focus? i only know how to use the BEGIN_MESSAGE_MAP and END_MESSAGE_MAP.. is there a way to make this message map dynamically?

thanks for the help Smile | :)

still a newb.. cut me some slack :P
-dz

Re: Dynamic CEdit can't call DoDataExchange()?

Sara Burns6-Dec-02 11:00

Sara Burns

6-Dec-02 11:00

I think you need to handle this using the OnCommand message if you have created a dynamic control.

Sara

Re: Dynamic CEdit can't call DoDataExchange()?

worm7-Dec-02 14:43

worm

7-Dec-02 14:43

Look at
ON_CONTROL_RANGE

Change window style

Member 997186-Dec-02 8:19

Member 99718

6-Dec-02 8:19

I'm using MFC's and MDI`s,I can change the window style after the creation of the window?

Re: Change window style

Maximilien6-Dec-02 8:30

Maximilien

6-Dec-02 8:30

Yes, some of the styles can be changed ( dependent on the Cwnd ( derived Cnwd ).

look at CWnd::ModifyStyle and CWnd::ModifyStyleEx

Max.

Re: Change window style

Member 997186-Dec-02 9:29

Member 99718

6-Dec-02 9:29

Thanks

Hovering text...

Maximilien6-Dec-02 8:01

Maximilien

6-Dec-02 8:01

Good morning,

I'm trying to have a small window to hover over my view (opengl ), following the mouse; a bit like a toolip, but needs to stay, not hide after a small delay.

so, I created a CWnd derived class with the text and all the trimmings, added _TrackMouseEvent to the view to be able to receive the WM_MOUSELEAVE and WM_MOUSEHOVER so that the window is shown only if the mouse is over the view's client.

It's working, but the display is bad, I have bad refresh.

I move the windows on the MouseMove of the view, it works ok, but it will, I think, trigger a redraw, so I get too much flicking ( even with double buffer ).

The question, is there way to make the hover window behave more like it was a overlay thing ?

Oh Bugger!, I'm just answering the question when writing this ... the parent window of the my Cwnd was bad ... much better ...

move on... just crazy programmer ... nothing to see ... move on ...

Max.

Detected memory leaks! :(

lucy6-Dec-02 7:04

lucy

6-Dec-02 7:04

help me please, I am stucked here. Mad | :mad:

It's a very simple SDI application. I got it from MFC appWizard.

In the view class, I started a worker thread, which will be running until a flag is cleared. I made sure that the worker thread is ended before the program terminate, because I put a TRACE line before its return statement, and the line is outputed. But still, I got such info:

Detected memory leaks!
Dumping objects ->
thrdcore.cpp(166) : {97} client block at 0x00305BB0, subtype 0, 112 bytes long.
a CWinThread object at $00305BB0, 112 bytes long
Object dump complete.

To make it more annoying, this doesn't happen all the time. What can go wrong? Confused | :confused:

Any clue is appreciated!

Re: Detected memory leaks! :(

Roger Allen6-Dec-02 7:23

Roger Allen

6-Dec-02 7:23

As its a CWinThread object thats been leaked, you can either store the pointer when you create the thread or set the m_bAutoDelete member var to true so it deletes itself when the thread ends.

Roger Allen
Sonork 100.10016

In case you're worried about what's going to become of the younger generation, it's going to grow up and start worrying about the younger generation. - Roger Allen, but not me!

Re: Detected memory leaks! :(

lucy6-Dec-02 7:32

lucy

6-Dec-02 7:32

Thank you for your quick help.

I set it, but it didn't solve the problem. anything else? Confused | :confused:

Re: Detected memory leaks! :(

lucy6-Dec-02 7:37

lucy

6-Dec-02 7:37

I noticed that after I rebuild the project then run it for the first time, this memory leak will occur for sure. The subsequent running doesn't have this problem. Why this inconsistence? Confused | :confused:

Re: Magic of StdAfx.h??

lucy6-Dec-02 8:00

lucy

6-Dec-02 8:00

It seemed that after I add #include "StdAfx.h" to my generic cpp file, this problem is solved.

But in my generic cpp file, all I did is some mathematical computation. No input or output involved, except for the argument passing to the function.

What does StdAfx.h do here? Why I have to include it? It makes no sense to me. Dead | X|

MFC Controls and Thread Safety :: MFC

valikac6-Dec-02 6:38

valikac

6-Dec-02 6:38

Hi.

I read an interesting thread at a MSDN newgroup on MFC and thread safety. Its author asks about why a thread causes the process to hang when you pass to the thread points to MFC control objects (CListrCtrl, CEdit, CTreeCtrl, etc).

I remember something similar to what the author of thread asks from a application I just finished. I found that you can make changes to MFC controls from threads via pointers to the controls. Everything works well until you call WaitForSingleObject(), or WaitForMultipleObject(), etc. In other words, the process hangs if you call WaitForSingleObject() when the thread is updating an MFC control.

Ivan Lalis posted an interesting solution involving MFC controls handles. He writes that one solution is to pass in the worker threads handles to MFC controls instead of pointers.

-----
UINT theWorkerThread(LPVOID pParam)
{
CListCtrl theList;
theList.attach(handleToRealListbox);
...
theList.detach();
return 0;
}
-----

I would like to know what is the safest solution to this problem? Secondly, in terms of Lalis' solution, do you create and attach, for example, one CListCtrland for the entire life-time of the thread?

Thanks,
Kuphryn

German characters

RAZ6-Dec-02 6:06

RAZ

6-Dec-02 6:06

Does anyone know how to print the German characters öäü to a line printer (Epson LX-300). I suppose I need to select a character set to do this, but somehow I can not manage to get it workin.

Thanks,
Richard

how to get the data of video card to store as BMP?

jarred6-Dec-02 6:07

jarred

6-Dec-02 6:07

:-DI want to get the data from video card and store them as Bmp.Please tell me how to do? Thanks a lot!

thanks to every one!

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