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Safe way of passing WNDPROC through functions S van Leent9-Jul-02 8:51 S van Leent 9-Jul-02 8:51  Is experimented with both on the heap and on the stact to pass a __stdcall (WNDPROC) to different functions. But the program (and explorer.exe!) crashes when I do so. Does anyone know how to safely pass a CALLBACK through a function. eg: WNDPROC xproc; LRESULT CALLBACK WindowProc(...) { } void a() { b((WNDPROC)WindowProc) } void b(WNDPROC wndproc) { // Do something like: xproc = wndproc; c(); } void c() { SetWindowLong(hWnd, GWL_WNDPROC, (long)xproc); } Don't try this! Thanks in advance, Sjoerd van Leent LPCSTR Dutch = "Double Dutch " Re: Safe way of passing WNDPROC through functions Joaquín M López Muñoz9-Jul-02 13:06 Joaquín M López Muñoz 9-Jul-02 13:06  There are a couple of issues in your code (maybe they are due to the fact that you have deleted some stuff in your post): The right signature for WindowProc is LRESULT CALLBACK WindowProc(HWND hwnd,UINT uMsg,WPARAM wParam,LPARAM lParam) WindowProc should return a value. Also, typically you will forward most calls to DefWindowProc: LRESULT CALLBACK WindowProc(HWND hwnd,UINT uMsg,WPARAM wParam,LPARAM lParam) { return DefWindowProc(hwnd,uMsg,wParam,lParam); } Apart from this, the code seems just fine. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Safe way of passing WNDPROC through functions S van Leent9-Jul-02 23:08 S van Leent 9-Jul-02 23:08  That was indeed for easyness sake Sjoerd LPCSTR Dutch = "Double Dutch " 'asynchronous' version of _access() Srini Kella9-Jul-02 8:08 Srini Kella 9-Jul-02 8:08  Guys: I need to test the existence of a file on Novell server. I could use _access() function. But, under some conditions (example: when the Novell Server is in the process of shut-down), the _access() function takes very long time to return to the caller. So, what I need is a scheme which will enable me testing the existence of a file asynchronously. The Async version of access() should check the file existence and notify the caller once it is done with the file check. Thanks in advance. Re: 'asynchronous' version of _access() Joaquín M López Muñoz9-Jul-02 12:57 Joaquín M López Muñoz 9-Jul-02 12:57  Try using CreateFile in FILE_FLAG_OVERLAPPED mode (this probably will work only in NT/2k/XP systems.) Joaquín M López Muñoz Telefónica, Investigación y Desarrollo RTF to XML AlexMarbus9-Jul-02 6:58 AlexMarbus 9-Jul-02 6:58  Not sure whether I should post this in the VC++ section or XML, but since I request code, VC++ seemed the best place to me. I'm searching for a piece of sourcecode that will convert RTF data to XML. Preferrably plain C++, not using MFC or anything else. Any hints on how to do this would be just as great. The goal is to save a piece of RTF formatted data between a single XML tag. -- Alex Marbus www.marbus.net But then again, I could be wrong. Re: RTF to XML Joaquín M López Muñoz9-Jul-02 13:26 Joaquín M López Muñoz 9-Jul-02 13:26  Hi Alex, I've just downloaded and tried IRun RTF Converter 1.11. It comes with an utility program that seems to work just fine. Also, it provides a .DLL you can use in your apps (not exactly source code, but it's probably the next best thing.) The whole thing is freeware. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: RTF to XML AlexMarbus10-Jul-02 7:41 AlexMarbus 10-Jul-02 7:41  Thanks Joaquín. The main issue is that is really must be platform independent (thus, standard C++). However, I read on the website (http://www.pilotltd.com/irun/) that the sourcecode is available on request. I think I might contact them (unless somebody else knows a better solution?) -- Alex Marbus www.marbus.net But then again, I could be wrong. Calling Access File TommyKnocker9-Jul-02 6:37 TommyKnocker 9-Jul-02 6:37  i want to execute an *.mdb file by my cpp program... does anyone know how to do this??? thanx for all answers... Re: Calling Access File Prem Kumar9-Jul-02 7:34 Prem Kumar 9-Jul-02 7:34  Ok, first of all *.mdb files are not executables! But I think what you want to do is open the mdb file in Access ?? Is that right ? If so you can use ShellExecute(..) ; with lpOperation as "open". SelectObject() Rules Obliterator9-Jul-02 6:32 Obliterator 9-Jul-02 6:32  Hi all, I'm suffering a major resource leak on Win95/98/Me in one of my drawing routines. I realise that before an object is destroyed one must ensure it is not selected in the device context by selecting the old object beforehand. However where my knowledge is lacking is with the use of multiple pens: For example suppose I have a red and a blue pen. Currently I store the old pen when selecting the red. I then use the red pen. Next I select the blue pen, ignoring the returned pen. After using the blue pen, before exiting I reselect the old pen (stored when selecting the red) I then call DestroyObject for both the red and blue pens. Is this sufficient or must I store the oldpen each time and restore it before selecting a new one? Surely not?! This leak is driving me insane! I know the leak is in this function because if I remove the call no crash occurs. However I cannot for the life of me see the leak! I've tried using the example here on CP to Save and Restore the DC state before and after drawing, without success. Thanks -- The Obliterator Re: SelectObject() Rules Prem Kumar9-Jul-02 7:32 Prem Kumar 9-Jul-02 7:32  If you are using MFC, every thing is taken care of if all the objects are local objects. But if you are programming in SDK you need to make calls to DeleteObject with the resource handle. Re: SelectObject() Rules Obliterator9-Jul-02 12:06 Obliterator 9-Jul-02 12:06  I'm using MFC - and all is definitely not taken care of! Anyhow it looks like I've finally found the leak - I'll be testing on Win9x tomorrow to be sure! There was a pen constructed inside an if statement then selected. The old pen should have been reselected before leaving the if statement. As it was not I'm guessing the pen could not be correctly destroyed as its scope was lost. Thanks anyhow. -- The Obliterator Re: SelectObject() Rules Michael Dunn9-Jul-02 19:25 Michael Dunn 9-Jul-02 19:25  Correct, a GDI object that is selected into a DC cannot be destroyed. --Mike-- Just released - RightClick-Encrypt v1.3 - Adds fast & easy file encryption to Explorer My really out-of-date homepage Sonork-100.19012 Acid_Helm Re: SelectObject() Rules Obliterator9-Jul-02 23:14 Obliterator 9-Jul-02 23:14  Wouldn't you have thought it could assert in the destructor if selected in the DC??? -- The Obliterator Re: SelectObject() Rules Anonymous10-Jul-02 11:33 Anonymous 10-Jul-02 11:33  Check your knowledge on DC b4 replying.. Sudip Stupidity Sucks Copy from Screen to Bitmap NickOne9-Jul-02 6:29 NickOne 9-Jul-02 6:29  Hello all, I'd like ot copy from the screen to a bitmap. I have an MDI application that opens DIBs. After I open one, I'd like to get this DIB from the screen as a new bitmap in a new window. I read the VC++ 6.0 Bible and they said just do this void CDisplayDIBView::GetImage(int x, int y, CDC *pDC, CBitmap *pBitmap) { BITMAP bm; pBitmap->GetObject( sizeof(BITMAP), &bm); CDC MemDC; MemDC.CreateCompatibleDC(pDC); CBitmap *pOldBitmap = MemDC.SelectObject(pBitmap); MemDC.BitBlt(0, 0, bm.bmWidth, bm.bmHeight, pDC, x, y, SRCCOPY); MemDC.SelectObject(pOldBitmap); } Well when I do this, I get an error saying the instruction at 0x5f47c360 referenced memory at 0x000000e. The memory could not be "read." How would I go about correcting this, or accomplishing what I want to do? Thanks a whole lot, NickOne Re: Copy from Screen to Bitmap Chris Losinger9-Jul-02 8:01 Chris Losinger 9-Jul-02 8:01  NickOne wrote: Well when I do this, I get an error which line gives you the error? is pDC valid? is pBitmap non-NULL? -c Being just contaminates the void.   --Robyn Hitchcock Image Processing - easy, like Sunday morning. Re: Copy from Screen to Bitmap Ernest Laurentin9-Jul-02 8:32 Ernest Laurentin 9-Jul-02 8:32  First make sure that your bitmap is not larger than your screen or the offset that you passed (x,y) are not playing against you. Make sure your bitmap object is not null or too small. Maybe you need to call CreateCompatibleBitmap(...) with your bitmap object. Good luck! Last Article: Adding VBScript/JScript to C++ App System tray Anonymous9-Jul-02 5:33 Anonymous 9-Jul-02 5:33  Hello everyone! Does anyone knows how tu use the system tray ? Thanks for your answers Re: System tray Joaquín M López Muñoz9-Jul-02 5:41 Joaquín M López Muñoz 9-Jul-02 5:41  If you refer to system tray icons, Chris Maunder's Adding Icons to the System Tray will probably cover all of your needs. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: System tray Renjith Ramachandran10-Jul-02 1:26 Renjith Ramachandran 10-Jul-02 1:26  yaa it is easy NOTIFYICONDATA gl_sNotifyIconData; gl_sNotifyIconData.cbSize=sizeof(NOTIFYICONDATA); strcpy(gl_sNotifyIconData.szTip,"your Tool tip here"); gl_sNotifyIconData.uID=FTPTRAYID; gl_sNotifyIconData.hIcon=AfxGetApp()->LoadIcon(ID of ur tray ICON); gl_sNotifyIconData.uCallbackMessage=the Message ID of ur app here; gl_sNotifyIconData.hWnd=this->m_hWnd; gl_sNotifyIconData.uFlags=NIF_ICON|NIF_MESSAGE|NIF_TIP; Shell_NotifyIcon(NIM_ADD,&gl_sNotifyIconData); this will put the icon in to your system tray and everythime u enter mouse over it it post some messages so it is necessery to trap the message by adding the ON_MESSAGE(messageID,onmessage) in your messagemap and add a function like onmessage(WPARAM wparam,LPARAM lparam) { wparam contains the trayID and lparam caontains the message handle them according to ur need } Renjith-CPian. Dialog controls Anonymous9-Jul-02 5:31 Anonymous 9-Jul-02 5:31  Hello How can you make a dialog that doesn't take the control of the application (wait for the answer of DoModal)like the tool windows of psp for example... Re: Dialog controls Joaquín M López Muñoz9-Jul-02 5:38 Joaquín M López Muñoz 9-Jul-02 5:38  These are called modeless dialogs. Search for these words on your documentation. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Dialog controls Anonymous9-Jul-02 5:51 Anonymous 9-Jul-02 5:51  Thank you!

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