Re: Problem in performance of calling a dialog in DLL(Windows prog
Hi dear Giovanni!
I really don't know how should I Thank you!!
your code is complete and better of mine,but I would ask some questions of
my own code from you;
My problem Solved with removing static part of p declaration!
And about Memory leaks:
static buff* pad = new buff;
I agree with you Tom that this line is wrong
The reason of static definition of pad is that I want to keep its last
value!
Because if I dont define static,can not transmit its values to this section:
if(LOWORD (wParam) == IDOK)
{
....
}
Moreover, I ultimately want to pass pad s new value to SecondFunction()
through final argument of DialogBoxParam!
BTW,if I free pad ,it can not transmit its new value(Selected substring
and its length )to SecondFunction()!
(in next lines of codes he reassigns 'pad' to another >value and Loose the 'new buff' dynamic allocated memory).
I think you mean this part:
if(LOWORD (wParam) == IDOK)
{
pad->m_ReaderBuff=new TCHAR[pad->size];
pad->m_ReaderBuff[0]='\0';
while(pReaderName[a]!='\0')
{
pad->m_ReaderBuff[a] = pReaderName[a] ;
a++;
}
pad->m_ReaderBuff[a]='\0';
pad->size=iLength;
delete[] pReaderName;
//delete pad;
//delete[] pad->m_ReaderBuff;
EndDialog (hwndDlg, TRUE) ;
return TRUE ;
}
I cant free pad before this section, because I need pad->size value in
the first line;
And I want to assign the new substring to m_ReaderBuff parameter of pad
structure,that is why I new pad->m_ReaderBuff in this section and also I
cant delete it, because I want it to keep its last value to transmit to
SecondFunction()!
But, I freed TCHAR* Reader=new TCHAR[30]; in the WM_INITDIALOG and then
Memory leaks information would be reduced!
I think that the OP might want to better study 'static' >keyword and memory allocations and freeing of C++.
Yes, youre right!
I still have many problems in memory allocations and freeing of C++
Could you introduce me any Excellent and Comprehensive reference of memory
allocations and freeing of C++ topic?
And What section of MSDN library do you suggest me to study well?
Moreover, he would benefit from using some C++ utility >class like CString, instead of raw TCHAR arrays
Yes, its a good case,but I would try TCHAR arrays,because in "Win32" we
don't have "CString" or generally "Class" concept!
And my dll is written in "Win32" and can't use of "CString", my MFC code
just calls the Secondfunction() of dll!
These lines added to detect memory leaks:
#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
_CrtDumpMemoryLeaks();
And the result after debugging was such below:
Detected memory leaks!
Dumping objects ->
{142} normal block at 0x003898F8, 92 bytes long.
Data: <A C S R E A D > 41 00 43 00 53 00 20 00 52 00 45 00 41 00 44 00
{133} normal block at 0x003897E8, 8 bytes long.
Data: < > CD CD CD CD CD CD CD CD
{61} client block at 0x00386F40, subtype c0, 64 bytes long.
a CDynLinkLibrary object at $00386F40, 64 bytes long
Object dump complete.
'Tester.exe': Unloaded 'D:\Program Files\Common Files\Microsoft
Shared\INK\PENUSA.DLL'
'Tester.exe': Unloaded 'D:\WINDOWS\system32\shell32.dll'
'Tester.exe': Unloaded 'D:\WINDOWS\ime\sptip.dll'
'Tester.exe': Unloaded 'D:\WINDOWS\ime\spgrmr.dll'
Detected memory leaks!
Dumping objects ->
{142} normal block at 0x003898F8, 92 bytes long.
Data: <A C S R E A D > 41 00 43 00 53 00 20 00 52 00 45 00 41 00 44 00
{133} normal block at 0x003897E8, 8 bytes long.
Data: < > CD CD CD CD CD CD CD CD
Object dump complete.
The program '[2676] Tester.exe: Native' has exited with code 0 (0x0).
But these lines dont show the code line in which memory leak has occurred
when I double click them(as described in MSDN)!!
I also read "How to: Set Breakpoints on a Memory Allocation Number"
On MSDN,but couldnt set Breakpoints because the debugger didnt recognize
_crtBreakAlloc or {,,msvcr71d.dll}_ crtBreakAlloc in the Watch Window!!
Could I ask you how found the code lines related to memory leaks?
And Finally:
Do you have any other suggestion and modification to this code regarding my
purpose?!
Thanks a lot,
"Giovanni Dicanio" wrote:
"creative22" <creative22@discussions.microsoft.com> ha scritto nel messaggio
news:9FF91E76-2175-420F-802A-851B696ADC4B@microsoft.com...
[...]
Could I ask you tell me what the problem is with this code?
Any help would be greatly appreciated,
In addition to other answers, I tried rewriting your code to try to show the
use of robust container classes like std::vector and CString class to store
strings.
I did some modifications to original code, e.g.:
* The 'buff' struct is not required at DLL interface, so I moved it away
from public DLL header and put it in private DLL implementation file
(DlgInDLL.cpp)
* I rewrote the 'buff' struct storing an array of CString's inside, instead
of the unique string with \0 termination of substrings plus explicit size
field.
In this way you make the code simpler because you don't need complex and
error-prone parsing code.
Moreover, you make your life easier using robust container and string
classes instead of TCHAR* raw pointers.
* I rewrote the DLL import/export #define
* I tried to indent the code a bit better (I think that code indentation is
a very important point of quality code)
You can find the new project here:
http://www.geocities.com/giovanni.dicanio/vc/DlgInDLL.zip
The source (DlgInDLL.cpp) and header (DlgInDLL.h) files of the DLL are also
copied below.
HTH,
Giovanni
[DlgInDLL.cpp]
//////////////////////////////////////////////////////////////////////////
// DlgInDLL.cpp
//////////////////////////////////////////////////////////////////////////
// Export from DLL
#define DLGINDLL_API __declspec(dllexport)
#include <windows.h> // Win32 SDK
#include <vector> // STL vector
#include <atlstr.h> // CString
#include "DlgInDLL.h" // DLL public header
#include "resource.h"
struct Buff
{
// List of strings to fill the combobox with
std::vector< CString > Strings;
// The string chosen by the user
CString UserChoice;
};
// DLL instance handle
static HINSTANCE g_hModule = NULL;
//------------------------------------------------------------------------
// DllMain
//------------------------------------------------------------------------
BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason,LPVOID lpvReserved)
{
if (fdwReason == DLL_PROCESS_ATTACH)
{
DisableThreadLibraryCalls(hinstDLL);
g_hModule = hinstDLL;
}
return TRUE;
}
//------------------------------------------------------------------------
// Dialog-box procedure - handles messages
//------------------------------------------------------------------------
BOOL CALLBACK SecondDlgProc(HWND hwndDlg,
UINT message,
WPARAM wParam,
LPARAM lParam)
{
// Store 'buf' parameter when WM_INITDIALOG is called.
// This is used to exchange data with caller function.
static Buff * buff = NULL;
switch (message)
{
case WM_INITDIALOG:
//
// *** Dialog Initialization ***
//
// Save buffer pointer
buff = reinterpret_cast<Buff *>( lParam );
// Clear contents of the combobox
SendDlgItemMessage(hwndDlg, IDC_COMBO1, CB_RESETCONTENT, 0, 0);
// Add strings to combobox
for (size_t i = 0; i < buff->Strings.size(); i++)
{
SendDlgItemMessage(
hwndDlg,
IDC_COMBO1,
CB_ADDSTRING,
0,
(LPARAM) buff->Strings[i].GetString()
);
}
return TRUE;
case WM_COMMAND:
if ( LOWORD (wParam) == IDOK )
{
//
// *** OK Button Pressed ***
//
//
// Get current selection
//
int index = (int) SendDlgItemMessage(hwndDlg, IDC_COMBO1,
CB_GETCURSEL, 0, 0);
int length = (int) SendDlgItemMessage(hwndDlg, IDC_COMBO1,
CB_GETLBTEXTLEN, index, 0) + 1 ;
if (length > 0)
{
std::vector<TCHAR> readerName(length);
SendDlgItemMessage(hwndDlg, IDC_COMBO1, CB_GETLBTEXT, index,
(LPARAM) (&readerName[0]) );
// Store it in string class
buff->UserChoice = &readerName[0];
}
else
{
// Empty string
buff->UserChoice = _T("");
}
EndDialog( hwndDlg, TRUE );
return TRUE ;
}
else if ( LOWORD (wParam) == IDCANCEL )
{
//
// *** Cancel Button Pressed ***
//
EndDialog( hwndDlg, FALSE );
return TRUE;
}
break;
}
return FALSE;
}
//------------------------------------------------------------------------
// Function exported by the DLL
//------------------------------------------------------------------------
DLGINDLL_API void WINAPI SecondFunction(void)
{
// Create buff struct on the heap
Buff * buff = new Buff();
// Fill the list of strings
buff->Strings.push_back(TEXT("ACS READER 0"));
buff->Strings.push_back(TEXT("ACS READER 1"));
buff->Strings.push_back(TEXT("ACS READER 2"));
// Show the dialog-box
if( DialogBoxParam(
g_hModule,
MAKEINTRESOURCE(IDD_DIALOG2),
NULL,
SecondDlgProc,
reinterpret_cast<LPARAM>(buff)) )
{
// Show the selected string to the user
CString msg;
msg.Format(_T("The value of reader is %s."),
buff->UserChoice.GetString());
MessageBox( NULL, msg, TEXT("Note"), MB_OK );
MessageBox( NULL, TEXT("The Second Function Succeeded."), NULL,
MB_OK);
}
else
{
MessageBox( NULL, TEXT("The Second Function Failed."), NULL,
MB_OK|MB_ICONERROR);
}
// Delete Buff structure
delete buff;
buff = NULL;
}
--------------------------------------------------------------------------
[DlgInDLL.h]
//////////////////////////////////////////////////////////////////////////
// DlgInDLL.h
//////////////////////////////////////////////////////////////////////////
#ifndef DLGINDLL_H
#define DLGINDLL_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef DLGINDLL_API
#define DLGINDLL_API __declspec(dllimport)
#endif /* DLGINDLL_API */
DLGINDLL_API void WINAPI SecondFunction(void);
#ifdef __cplusplus
}; /* extern C */
#endif
#endif /* DLGINDLL_H */
--------------------------------------------------------------------------