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The second is correct.
Steve
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Thanks Stephen,
Your confirmation makes me more confident. 
regards,
George
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I have done the basics in creating a simple GUI framework. Set the WNDCLASSEX with lpfnWndProc pointing to a static member function of my base window class. Calling CreateWindowEx with the appropriate parameters returns a valid HWND. This works well for the main form. Its drawn properly, no problems.
When I create a child window and initialize it as mentioned it runs ok; the global WNDPROC routes all messages via the SetWindowLong/GetWindowLong to the window and they are handled ok. ALL BUT THE WM_PAINT MESSAGE. The application crashes with a runtime error. The same occurs with WM_NCPAINT.
WM_GETMINMAXINFO, WM_CREATE, WM_NCCREATE etc are all working well, except the paint messages.
Here's the global WNDPROC.
<br />
LRESULT CALLBACK<br />
WinControl::GlobalWndProc(HWND pHWnd, UINT pMsg, WPARAM wParam, LPARAM lParam)<br />
{<br />
LRESULT nResult = 0;<br />
<br />
WinControl * nControl = NULL;<br />
<br />
MSG nMsg = { 0 };<br />
<br />
WinCriticalSection nLock;<br />
<br />
LPCREATESTRUCT nLPStruct = { 0 };<br />
<br />
nLock.Lock();<br />
<br />
nControl = reinterpret_cast<WinControl *>(::GetWindowLong(pHWnd, GWL_USERDATA));<br />
<br />
if((nControl == NULL) && (pMsg == WM_NCCREATE))<br />
{<br />
nLPStruct = reinterpret_cast<LPCREATESTRUCT>(lParam);<br />
<br />
nControl = reinterpret_cast<WinControl *>(nLPStruct->lpCreateParams);<br />
<br />
::SetWindowLong(pHWnd, GWL_USERDATA, (LONG)nControl);<br />
}<br />
<br />
if(nControl == NULL<br />
{<br />
nResult = ::DefWindowProc(pHWnd, pMsg, wParam, lParam);<br />
}<br />
else<br />
{<br />
nMsg.hwnd = pHWnd;<br />
<br />
nMsg.lParam = lParam;<br />
<br />
nMsg.wParam = wParam;<br />
<br />
nMsg.message = pMsg;<br />
<br />
nResult = nControl->WndProc(&nMsg);<br />
<br />
nControl = NULL;<br />
}<br />
<br />
nLock.Unlock();<br />
<br />
return nResult;<br />
}<br />
<h>Hope is the remainder of the of the number of times you thought you wouldn't make it divided by infinity. - e.m
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You're using some third party library that likely has bugs.
You do not need, nor should you, use a critical section in your main procedure.
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
modified on Monday, February 18, 2008 10:12 PM
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Joe Woodbury wrote: You're using some third party library that likely has bugs.
My project has no external dependencies other than those windows provided. Am trying to build a GUI framework from the ground up.
Joe Woodbury wrote: You do not need, nor should you, use a critical section in your main procedure.
You're right there, had not done enough reading.
This bug is starting to get to me.
<h>Hope is the remainder of the of the number of times you thought you wouldn't make it divided by infinity. - e.m
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I don't see any problems in the code you've shown.
Where is it crashing? Stepping into the nControl->WndProc(&nMsg) call
on a WM_PAINT message - where does it crash?
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif)
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I stepped through the
nControl->WndProc(Msg & nMsg)
and found that nControl was not a valid pointer. This was irregular because it only happened when the WM_PAINT and the WM_NCPAINT were sent to the window.
Here's the history:
I have a class, WinControl that is responsible for wrapping methods related to manipulation of a windows control. It has a RegisterWindowClass method that creates the WNDCLASSEX passing it to the the native RegisterClassEx API function. The lpfnWndProc is set to point to a public static GlobalWndProc member function of the WinControl class.
Upon window creation using CreateWindowEx all windows messages are passed to the GlobalWndProc function. In here the HWND sent by windows is associated with the WinControl being created (when the WM_NCCREATE message is received):
SetWindowLong(theHWND, GWL_USERDATA, pointerToTheWinControlObtainedFromTheLPARAM)
On subsequent system messages, the WinControl mapping to the HWND supplied by the system is retrieved by:
GetWindowLong(theHWND, GWL_USERDATA)
Once retrieved the message is passed to a protected WndProc method in the WinControl class where using the this pointer, the window is able to consume it appropriately.
The problem was arising because the retrieval of the WinControl was failing, specifically during the WM_PAINT message.
After lots of cursing, gnashing of teeth, the following workaround seems to have settled the issue:
1. Associate the WinControl's HWND using:
static VOID
AssociateControlWithHWnd(IN CONST WinControl * pControl,
IN CONST HWND pHWnd)
{
if(pHWnd != NULL)
{
SetWindowLongPtr (pHWnd, 0, 0);
SetWindowLongPtr (pHWnd, 8, (LONG_PTR) pControl);
SetWindowLongPtr (pHWnd, GWLP_USERDATA, improbableWindowNumber);
}
}
2. Retrieve the WinControl's HWND using:
static WinControl *
GetControlFromHWnd(HWND pHWnd)
{
if((pHWnd != NULL) && (::GetWindowLong(pHWnd, GWLP_USERDATA) == improbableWindowNumber))
{
return reinterpret_cast<WinControl *>GetWindowLong(pHWnd, 8));
}
return NULL;
}
where improbableWindowNumber = 0xf965aa01.
I bumped onto JUCE and after a tweaking a thing or two, with the above code, the nControl was retrieved successfully and all messages were routed without any problems.
And that is half a day of my life I will never get back.
Thanks for the concern.
<h>Hope is the remainder of the of the number of times you thought you wouldn't make it divided by infinity. - e.m
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could anyone tell me briefly how this code is working?please help me.
<br />
<br />
<br />
#include "tools.h"<br />
<br />
#include "ltisys.h"<br />
<br />
#include "nonrec.h"<br />
<br />
<br />
<br />
int main()<br />
<br />
{<br />
<br />
Graph gr(3,2,"Non-Recursive Filter Design");<br />
<br />
<br />
<br />
<br />
LTISystem lp = NRLowPass(0.1,63);<br />
<br />
lp.a.plot(gr,1,"Low-pass at 0.1","Samples","Amp");<br />
<br />
<br />
<br />
<br />
Spectrum lpf(500,1000);<br />
<br />
for (int i=0;i<500;i++) lpf[i] = lp.response(i/1000.0);<br />
<br />
lpf.plotLogMag(gr,2,"Frequency Response");<br />
<br />
<br />
<br />
<br />
LTISystem hp = NRHighPass(0.4,63);<br />
<br />
hp.a.plot(gr,3,"High-pass at 0.4","Samples","Amp");<br />
<br />
<br />
<br />
<br />
Spectrum hpf(500,1000);<br />
<br />
for (int i=0;i<500;i++)<br />
<br />
hpf[i] = hp.response(i/1000.0);<br />
<br />
hpf.plotLogMag(gr,4,"Frequency Response");<br />
<br />
<br />
<br />
<br />
LTISystem bp = NRBandPass(0.2,0.3,63);<br />
<br />
bp.a.plot(gr,5,"Band-pass at 0.2-0.3","Samples","Amp");<br />
<br />
<br />
<br />
<br />
Spectrum bpf(500,1000);<br />
<br />
for (int i=0;i<500;i++) bpf[i] = bp.response(i/1000.0);<br />
<br />
bpf.plotLogMag(gr,6,"Frequency Response");<br />
<br />
<br />
<br />
gr.close();<br />
<br />
}<br />
<br />
<br />
<br />
#include "tools.h"<br />
<br />
#include "ltisys.h"<br />
<br />
#include "nonrec.h"<br />
<br />
#include "kaiser.h"<br />
<br />
<br />
<br />
const int MAXKAISERWIN=256;
<br />
<br />
<br />
<br />
LTISystem KaiserLowPass(<br />
<br />
double freq,
<br />
<br />
double ripple,
<br />
double twidth
<br />
<br />
)
<br />
{<br />
<br />
int i;<br />
<br />
<br />
<br />
<br />
Waveform kwin = Kaiser(ripple,twidth,MAXKAISERWIN);<br />
<br />
int nhalf = kwin.count()-1;<br />
<br />
<br />
<br />
<br />
<br />
double omega = 2*PI*freq;<br />
<br />
for (i=0;i<=nhalf;i++)<br />
<br />
kwin[i+1] *= omega*sinc(i*omega)/PI;<br />
<br />
<br />
<br />
<br />
LTISystem lpfilt(2*nhalf,0);<br />
<br />
lpfilt.a[nhalf] = kwin[1];<br />
<br />
for (i=1;i<=nhalf;i++) {<br />
<br />
lpfilt.a[nhalf-i] = kwin[i+1];<br />
<br />
lpfilt.a[nhalf+i] = kwin[i+1];<br />
<br />
}<br />
<br />
<br />
<br />
return lpfilt;<br />
<br />
}<br />
<br />
<br />
<br />
<br />
<br />
<br />
int main()<br />
<br />
{<br />
<br />
int i;<br />
<br />
<br />
<br />
<br />
Graph gr (2,2,"Kaiser Window Design");<br />
<br />
<br />
<br />
<br />
Waveform kwv1 = Kaiser(40.0,0.005,MAXKAISERWIN);<br />
<br />
kwv1.plot(gr,1,"Kaiser (40dB/0.005)");<br />
<br />
<br />
<br />
<br />
LTISystem lp1 = KaiserLowPass(0.1,40.0,0.005);<br />
<br />
Spectrum lpf1(500,1000);<br />
<br />
for (i=0;i<500;i++) lpf1[i] = lp1.response(i/1000.0);<br />
<br />
lpf1.plotLogMag(gr,2,"Frequency Response");<br />
<br />
<br />
<br />
<br />
Waveform kwv2 = Kaiser(80.0,0.01,MAXKAISERWIN);<br />
<br />
kwv2.plot(gr,3,"Kaiser (80dB/0.01)");<br />
<br />
<br />
<br />
<br />
LTISystem lp2 = KaiserLowPass(0.1,80.0,0.01);<br />
<br />
Spectrum lpf2(500,1000);<br />
<br />
for (i=0;i<500;i++) lpf2[i] = lp2.response(i/1000.0);<br />
<br />
lpf2.plotLogMag(gr,4,"Frequency Response");<br />
<br />
<br />
<br />
gr.close();<br />
<br />
}<br />
<br />
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Try reading the article you copied this from: http://www.phon.ucl.ac.uk/courses/spsci/dsp/lpc.html[^]
If you don't understand digital signal processing, learn that first.
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
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ashwiny wrote: could anyone tell me briefly how this code is working?
Which part exactly?
"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Hi,
I'm trying to paint a Bitmap in my dialog. Got as far as:
CWnd* pWnd =GetDlgItem(IDC_LOGO);
if(pWnd){
CDC* pDC=pWnd->GetDC();
CBitmap Bmp;
Bmp.LoadBitmap(IDB_LOGO);
pDC->SelectObject(&Bmp);
// What Next to Paint it
}
My Bitmap painting skills are very seldomly excersised, and got a bit rusty as a result.
Bram van Kampen
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create a compatible dc using pDC.
select the Bmp in this compatible dc.
at last pDC->Bitblt(......compatible dc);
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ccpptrain is right,
using CImage is much simple
CImage img;
img.LoadFromResource(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDB_LOGO));
img.BitBlt((HDC)pDC, 0, 0);
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Thanx
I Never Knew that, but you can actually import a static Bitmap Resource direct into MS5++.
Actually that was all I was looking for.
Regards
Bram van Kampen
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I create a thread in a very simple app, that way:
<br />
HWND hWnd = CreateWindow(...);<br />
<br />
DWORD _tid;<br />
if((CreateThread(NULL, 0, msgprocessing, hWnd, 0, &_tid)) == NULL) {<br />
error();<br />
}<br />
I need tu run message processing in the thread to catch msg's for hWnd window, but it won't work. Everything else is coded correctly. Any ideas why 
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Hi,
have you tried to create the window in the thread that needs to catch the messages?
This should work.
codito ergo sum
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Hi,
U can create window in thread. The message of that window will pass though the PreTransalte and MessageLoop of the application .
If needed i hope u can implement you own message loop(in the thread itself) after the creation of window.
I do not know if the implementation of message loop in the thread will causue any problem withe the main message loop of the application.
Prasanth Vijay
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U can use PeekMessage() message for implementing the message catching loop.
See the help in MSDN.
If u have time, Plz have look on CWInApp::Run() or CWinThread::Run() in the MFC message implementation. This will give very good idea on the messaeg loop implemenattion.
Thanks
Prasanth Vijay
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I used the PeekMessage and tried to create the window in the secondary thread, but still not working. So I placed the whole code, here (sorry for the comments, they are not in ENG)
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Im wanting to allocate a button on a form to connect to an IP address on my network through TCP. A seperate button will send an ASCII code e.g "l" to the IP address and a third button will disconnect from the TCP connection. Im having trouble trying to do this using TcpClient in Visual C++ (express edition 2008 version). The main problem Im having is trying to seperate code for just connecting to the tcp conection, then having a seperate part of code to write to the data stream and a third part that just disconnects from the tcp connection. 
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Howdy out there...
I was wondering if anyone had some good guidelines for creating services.
Currenly I have a UI and and engine hooked together... The communicate a lot, and I'd like to split the engine off of the UI and make a service.
But, I was wondering if there were any good guidelines on this topic?
Thanks in advance!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
<a href="http://www.soonr.com">SoonR Inc -- PC Power delivered to your phone</a>
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I guess most important, is the first sentence here:
Services (Windows)[^]
The service shouldn't have any UI.
Other than the service control code, interprocess communication is the
only major change you should need.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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