memory leak problems? refreshing tree control.

What 'getHook(i);' does, allocates new object? If so, then old one is not freed.
Very same applies to getButton(i,k);

Either check for nonNULL before those two calls, and call delete(rHook) before assigning new value, or use
std::auto_ptr

> BUTTON* rBut;
> HOOK* rHook;
#include <memory>
std::auto_ptr<BUTTON> rBut;
std::auto_ptr<HOOK> rHook;

...
rHook.reset( getButton(i,k) ); //delete old(if any) object, keep new one
rHook.reset(); //delete object
rHook.release(); //don't delete the object, just forget the pointer, user have to delete it by itself
also, aut_ptr deletes the object it holds if the auto_ptr object is deleted. In such case it behaves like scoped ptr.

But note: the above is valid only if mentioned functions create new objects. If they return object kept in some structures, objects should not be deleted.

Also
getButtonProgram(i,k); getButtonOutput(i,k); return char*, but if it's newly allocated memory, then is never freed

when You strcat(), You sure You will not run outside the buffer? Maybe You should use c++ string class - it would reallocate itself automatically.

hi thanks for the reply,

the methods simply return an object held in the structure

HOOK* getHook(int i){ return hookFile.hooks[i]; }
BUTTON* getButton(int i, int j){ return hookFile.hooks[i]->buttons[j]; }

ok, i've replaced it with CString too and made a few changes however it still does the same if i add four item and click on a selection and randomly highlight differnet ones after a few click on of the entries becomes ||||||| and then when i close the dialog of or click another button i get the user break point.
heres the new method.

BUTTON* rBut;
HOOK* rHook;
char* var;
CString cVar;
CString x,y;
char tmp[10]; //needed for no conversion
TV_INSERTSTRUCT g_tree; //for listing the hook file
HTREEITEM nHook;
HTREEITEM nButton;
HTREEITEM nField;

ofstream logfile;

void CAddHookDlg::refreshHookFile()
{
      m_tree_button.DeleteAllItems(); //remove for refresh
      
      //now insert all hooks
      int i;
      for(i=0; i<maxHooks; i++)
      {
            rHook = getHook(i);

            if(rHook == NULL)
                  break;

            logfile.open( "refreshlog.txt", ios::app );
            logfile << "REFRESH:" << rHook->window << ": \n";
            logfile.close();

            g_tree.item.iImage=0; // not pressed pic
            g_tree.item.iSelectedImage=1; // pressed pic
            g_tree.hParent = NULL;
            g_tree.hInsertAfter = TVI_LAST;
            g_tree.item.mask=TVIF_TEXT|TVIF_IMAGE|TVIF_SELECTEDIMAGE;

            cVar = "HOOK:";
            cVar = cVar + rHook->window;
            var = (char*) malloc(strlen(cVar)+1);
            strcpy(var,cVar);
            g_tree.item.pszText = var;
            nHook=m_tree_button.InsertItem(&g_tree);
            free(var);
            
            //now add each button for this particular hook
            int k;
            for(k=0; k<maxButtons; k++)
            {
                  rBut = rHook->buttons[k];

                  if(rBut == NULL)
                        break;
                  
                  g_tree.item.iImage=0; // not pressed pic
                  g_tree.item.iSelectedImage=1; // pressed pic
                  g_tree.hParent = nHook;
                  g_tree.hInsertAfter = TVI_LAST;
                  g_tree.item.mask=TVIF_TEXT|TVIF_IMAGE|TVIF_SELECTEDIMAGE;

                  cVar = "BUTTON:";
                  cVar = cVar + rBut->text;
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  nButton=m_tree_button.InsertItem(&g_tree);
                  free(var);


                  g_tree.item.iImage=2; // not pressed pic
                  g_tree.item.iSelectedImage=2; // pressed pic
                  g_tree.hParent = nButton;
                              
                  cVar = "CLASS:";
                  cVar = cVar + rBut->bClass;
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);

                  x.Format("%d",rBut->dimensions->x);
                  y.Format("%d",rBut->dimensions->y);
                  cVar = "COORDS:[x" + x + ",y" + y + "]";
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);

                  cVar = "WIDTH:" + rBut->dimensions->width;
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);

                  cVar = "HEIGHT:" + rBut->dimensions->height;
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);

                  cVar = "ANCHOR:";      
                  int anchor = rBut->dimensions->anchor;

                  switch(anchor)
                  {
                  case 0:
                        cVar = cVar + "T_LEFT";
                        break;
                  case 1:
                        cVar = cVar + "T_RIGHT";
                        break;
                  case 2:
                        cVar = cVar + "B_LEFT";
                        break;
                  case 3:
                        cVar = cVar + "B_RIGHT";
                        break;
                  }

                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);


                  cVar = "PROGRAM:";
                  cVar = cVar + rBut->program;
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);

                  cVar = "OUTPUT:";
                  cVar = cVar + rBut->output;
                  var = (char*) malloc(strlen(cVar)+1);
                  strcpy(var,cVar);
                  g_tree.item.pszText= var;
                  m_tree_button.InsertItem(&g_tree);
                  free(var);

                  //now add fields on button
                  g_tree.item.iImage=0; // not pressed pic
                  g_tree.item.iSelectedImage=1; // pressed pic
                  g_tree.item.pszText= "FIELDS:";
                  nField = m_tree_button.InsertItem(&g_tree);

                  g_tree.item.iImage=2; // not pressed pic
                  g_tree.item.iSelectedImage=2; // pressed pic
                  g_tree.hParent = nField;

                  int l;
                  for(l=0; l<maxFields; l++)
                  {
                        if(rBut->fields[l]==NULL)
                              break;

                        cVar.Format("%d",rBut->fields[l]->fieldPath);
                        var = (char*) malloc(strlen(cVar)+1);
                        strcpy(var,cVar);
                        g_tree.item.pszText= var;
                        m_tree_button.InsertItem(&g_tree);
                        free(var);
                  }
            }
      }
}

i see this was what i tried at first however, the reason i've been copying the cVar into a char* var is because the compiler complained about cVar nt been a char*. this was the only way i could think of for casting cVar to a char* from a CString.

cVar.c_str() extracts const char * from the cVar. But it's not copy, it's reference to cVar internal structures.

hi ive tried

cVar = "BUTTON:";
cVar = cVar + rBut->text;
g_tree.item.pszText= cVar.c_str();
nButton=m_tree_hook.InsertItem(&g_tree);
free(var);

and it says c_str() is not a member of CString. also it says .append is not either when i try that.

Right, somehow I was thinking of std::string
http://msdn2.microsoft.com/en-us/library/awkwbzyc(VS.71).aspx#_core_converting_to_c.2d.style_null.2d.terminated_strings
either copy or cast.
In both cases if
g_tree.item.pszText;
is char *, then it will dereference already freed memory;

ok. thanks i've also found another problem that is related (i think ) to memory problems. In my program i have an open button which will read in a file and fill in the structure.

If i run this the first time then it works with no problems, however if i then try and rea din the same file that it read in successfully before i get a user break point exception again.

This seems to happen at different points in the program. I have noticed that every now and again it causes an access violation on this method

void addButton(CString hook, CString text, CString bClass, int x, int y, int width, int height, int anchor, CString program, CString output, int* fields)
{
      int i;
      for(i=0; i<maxHooks; i++)
            if(strcmp(hookFile.hooks[i]->window,hook) ==0)
                  break;

      int j;
      for(j=0; j<maxButtons; j++)
            if(hookFile.hooks[i]->buttons[j] == NULL)
                  break;

      if(i<maxHooks && i<maxButtons)
      {
            BUTTON *pBut = (BUTTON*) GlobalAlloc(GPTR, sizeof(BUTTON));

            HGLOBAL memPtr = GlobalAlloc(GMEM_FIXED, strlen(bClass)+1); //pointer to mem block

            if( memPtr && (pBut->bClass = (LPTSTR)GlobalLock(memPtr)) != NULL )
                  RtlMoveMemory(pBut->bClass, bClass, strlen(bClass)+1);
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button class.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            memPtr = GlobalAlloc(GMEM_FIXED, strlen(text)+1); //pointer to mem block

            if( memPtr && (pBut->text = (LPTSTR)GlobalLock(memPtr)) != NULL )
                  RtlMoveMemory(pBut->text, text, strlen(text)+1);
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button text.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            DIMENSIONS *pDim = (DIMENSIONS*) GlobalAlloc(GPTR, sizeof(DIMENSIONS));

            memPtr = GlobalAlloc(GMEM_FIXED, sizeof(int)); //pointer to mem block

            if( memPtr && (pDim->x = (int)GlobalLock(memPtr)) != NULL )
                  pDim->x = x;
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button x coord.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            memPtr = GlobalAlloc(GMEM_FIXED, sizeof(int)); //pointer to mem block

            if( memPtr && (pDim->y = (int)GlobalLock(memPtr)) != NULL )
                  pDim->y = y;
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button y coord.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            memPtr = GlobalAlloc(GMEM_FIXED, sizeof(int)); //pointer to mem block

            if( memPtr && (pDim->height = (int)GlobalLock(memPtr)) != NULL )
                  pDim->height = height;
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button height value.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            memPtr = GlobalAlloc(GMEM_FIXED, sizeof(int)); //pointer to mem block

            if( memPtr && (pDim->width = (int)GlobalLock(memPtr)) != NULL )
                  pDim->width = width;
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button width value.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            memPtr = GlobalAlloc(GMEM_FIXED, sizeof(int)); //pointer to mem block

            if( memPtr && (pDim->anchor = (int)GlobalLock(memPtr)) != NULL)
                  pDim->anchor = anchor;
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button anchor.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            pBut->dimensions = pDim;

            memPtr = GlobalAlloc(GMEM_FIXED, strlen(program)+1); //pointer to mem block

            if( memPtr && (pBut->program = (LPTSTR)GlobalLock(memPtr)) != NULL )
                  RtlMoveMemory(pBut->program, program, strlen(program)+1);
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button program.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            memPtr = GlobalAlloc(GMEM_FIXED, strlen(output)+1); //pointer to mem block

            if( memPtr && (pBut->output = (LPTSTR)GlobalLock(memPtr)) != NULL )
                  RtlMoveMemory(pBut->output, output, strlen(output)+1);
            else
            {
                  char buf[128];
                  sprintf(buf, "Error Unable to allocate Memory for button output.");
                  MessageBox(NULL, buf, NULL, 0);
            }

            //now add fields
            addField(pBut,fields);

            hookFile.hooks[i]->buttons[j] = pBut;

      }
      else
      {
            char buf[128];
            sprintf(buf, "Unable to add button maxHooks=%d, maxButtons=%d", maxHooks, maxButtons);
            MessageBox(NULL, buf, NULL, 0);
      }
}

do you think this method which populates the button structure could be the problem? i've also raised the points to 500 ;) thanks for your help.

hi from using break points i think the problem is in the addButton method as it runs through this fine first time then on the second run through in my readfile method it breaks on calling this method