hWnd member of WndProc changed...

[xandaz]

    Hi guys. Is there any particular situation where the hWnd member of WndProc changes or gets set to null? I'm trying GetWindowText,hWnd,addr Buffer, sizeof Buffer and it doesn't work...

[HSE]

What is a member of WndProc?

[xandaz]

    I meant the PROTOTYPE member: hWnd. I'm going mad with this shit. Application gets lost in the memory space and it's not stack misaligned.

[xandaz]

    My programming is full of mud. All disorganized. just take a look at this

Code: [Select]

         .elseif ax==IDM_CLOSEPROJECT
            .if ProjectFlag==FALSE
                invoke  MessageBox,hMainWindow,addr szNoProjectOpened,addr szAttention,MB_OK
            .else
              invoke MessageBox,hMainWindow,addr szKeepChanges,addr szAttention,MB_YESNO
.if eax==IDYES
invoke SaveFiles
.endif
       mov ecx,noMdiChild
       or ecx,ecx
       jz    dont_build
       invoke CreateFile,addr szProjectBuffer,GENERIC_WRITE,\
FILE_SHARE_WRITE,0,CREATE_ALWAYS,\
FILE_ATTRIBUTE_NORMAL,0
       mov     hProject,eax
              invoke  BuildProjectFile,hMainWindow
invoke MessageBoxA,0,addr ProjectFileBuffer,0,MB_OK
              invoke  CountBytes2,addr ProjectFileBuffer
              invoke  WriteFile,hProject,addr ProjectFileBuffer,ecx,\
                                  addr noBytesWritten,0
              invoke CloseHandle,hProject
              mov     ecx,noMdiChild
              or     ecx,ecx
              jz        no_close
loop_32:
                push    ecx
                invoke  SendMessage,hMdi,WM_MDINEXT,0,TRUE
  invoke SendMessage,hMdi,WM_MDIGETACTIVE,0,0
  mov hCurrentWindow,eax
                invoke  GetWindowLong,eax,GWL_USERDATA
  mov edi,eax
  test [edi.MdiStruct].dwFlags,IDF_UNTITLED
  jz skip_32
  dec noUntitledChild
skip_32:
         invoke LocalFree,[edi.MdiStruct].lpTextBuffer
                invoke  SendMessage,hMdi,WM_MDIDESTROY,hCurrentWindow,0
                pop     ecx
  dec ecx
                dec     noMdiChild
  cmp ecx,0
  jne loop_32
no_close:
               .if ProjectFlag==TRUE
            invoke  SetWindowText,hMainWindow,addr MainWindowName
              invoke  ClearMemory,addr ProjectFileBuffer,sizeof ProjectFileBuffer
              invoke  ClearMemory,addr MdiStructs,sizeof MdiStruct*20
  mov ProjectFlag,FALSE
jmp _end

              .endif
dont_build:       
            mov     ProjectFlag,FALSE
.endif


[xandaz]

   The problem seems to be somewhere is this procedure:

Code: [Select]

SaveFiles PROC

local hWindow;DWORD
local UserData:DWORD

mov ecx,noMdiChild
loop_0:
push ecx
invoke SendMessage,hMdi,WM_MDINEXT,0,TRUE
invoke SendMessage,hMdi,WM_MDIGETACTIVE,0,0
mov hWindow,eax
invoke     GetWindowLong,eax,GWL_USERDATA
mov UserData,eax
test [UserData.MdiStruct].dwFlags,IDF_UNTITLED
jz skip_1
invoke GetCurrentDirectoryA,sizeof szInitialDir,addr szInitialDir
lea esi,szInitialDir
cld
loop_1:
lodsb
or al,al
jnz loop_1
dec esi
mov byte ptr [esi],'\'
inc esi
invoke GetWindowTextA,hWindow,esi,MAX_PATH
invoke CopyBufferA,addr szInitialDir,addr [UserData.MdiStruct].szFile
jmp create_file
skip_1:
invoke CopyBufferA,addr [UserData.MdiStruct].szFile,addr szInitialDir
create_file:
invoke MessageBoxA,0,addr szInitialDir,0,MB_OK
invoke CreateFileA,addr szInitialDir,GENERIC_WRITE,\
FILE_SHARE_WRITE,0,CREATE_ALWAYS,\
FILE_ATTRIBUTE_NORMAL,0
push eax
mov EditStream.dwCookie,eax
mov EditStream.pfnCallback,offset StreamOutProc
mov eax,UserData
invoke SendMessage,[eax.MdiStruct].hEdit,EM_STREAMOUT,SF_TEXT,addr EditStream
pop eax
invoke CloseHandle,eax
pop ecx
dec ecx
or ecx,ecx
jnz loop_0
ret
SaveFiles endp



[HSE]

Where you set the title?

[Greenhorn]

invoke   GetCurrentDirectoryA, sizeof szInitialDir, addr szInitialDir

Is the value of sizeof szInitialDir correct ?! I guess it should be MAXPATH ???
What's the return value of GetCurrentDirectoryA ?

You don't need the loop_1 to search the last char in szInitialDir, you can use the return value of GetCurrentDirectoryA.
Check always for errors.


invoke   GetCurrentDirectoryA,MAXPATH,addr szInitialDir
.if (eax && eax < MAXPATH - 2)
     lea  esi, szInitialDir
     mov  BYTE ptr [esi+eax], '\'
     inc  eax
     mov  BYTE ptr [esi+eax], 0
;;   invoke   GetWindowTextA,hWindow,addr [esi+eax],MAX_PATH  ;; This will lead to buffer overflow !!! Calculate the difference between EAX and MAXPATH !
     mov  edx, MAXPATH
     sub  edx, eax
     invoke   GetWindowTextA,hWindow,addr [esi+eax],edx
     .if (!eax)
          ;; Error handling ...
     .endif
.else
     ;; Error handling ...
.endif


I hope I got it right ...

Edith said I had to correct some parts ... 
Edith said: Do it again.
Edith said it's still erroneous, but now ... 
Edith said I'm a hopeless case ... 

[xandaz]

   Thanks. I appreciate the help. I didn't think it mattered the right size of the buffer.
   Edith said the same thing about me.

[Greenhorn]

I had to correct errors again. Post is updated.

[jj2007]

Is there any particular situation where the hWnd member of WndProc changes or gets set to null?

No. The OS calls WndProc, and always passes the handle in the same position:

WndProc proc hWnd, uMsg, wParam:WPARAM, lParam:LPARAM

[TimoVJL]

It depends of created windows in same classes.
Usually programmer creates only one frame window using registered windowclass with WndProc.

[hutch--]

JJ is correct here, a WndProc() is what is normally called a "callback". You tell the OS the name (location) in the WNDCLASSEX structure and the OS sends messages processed in the message loop to the WndProc.

[NoCforMe]

Small detail, but you need to save and restore ESI in your SaveFiles() procedure. Either PUSH and POP it, or put USES ESI in the proc declaration.