C / C++ / MFC

Fossi Bluman wrote:

...it throws an exceptions at run time...

n=fread (buf,sizeof (buf),size,fp);
printf ("\n%02x %lu bytes read",buf[15],size);

DavidCrow wrote:

Among other things, size is the number of bytes to read, whereas n is the number of bytes actually read.

size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);

FILE *f;
struct mystruct foo[10];
size_t n;
n = fread(foo, sizeof(struct mystruct), 10, f);

//******************************************
// reading an entire binary file the c++ way

#include <iostream>
#include <fstream>
using namespace std;

int main (){

  streampos size;
  char * memblock;
  cout<<" \n\n";

  // open file as binary
  ifstream file ("myfile.bin", ios::in|ios::binary|ios::ate);
  if ( file.is_open() ){

    // get file size
    size = file.tellg();

    // alloocate appropiate file size + 1 for '\0'
    memblock = new char [size+1];

    // go to begining of file
    file.seekg (0, ios::beg);

    // read entire file into ram memory
    file.read (memblock, size);
    file.close();

    // display size of file
    cout << "the entire file content of "<< size <<" bytes is in memory  \n\n\n";
 
    // release memory
    delete[] memblock;
  }
  else cout << "Unable to open file\n\n";

    
cout<<"Press ANY key to close.\n\n";
cin.ignore(); cin.get();
return 0;
}                         

ForNow wrote:

Second in my message handler the first thing I should is call the default handler
CWnd::OnNcPaint
Calling it at the end will wipe out whatever I have done correct ?

 WNDPROC SafeGetDialogProc(HWND hwnd)
{
    if(IsWindowUnicode(hwnd))
        return (WNDPROC)GetWindowLongPtrW(hwnd, DWLP_DLGPROC);
    else
        return (WNDPROC)GetWindowLongPtrA(hwnd, DWLP_DLGPROC);
}

case WM_NCPAINT: {
         WNDPROC OldHandler = SafeGetDialogProc(hwnd);    // Get dialog handler
         CallWindowProc(OldHandler, hwnd, Msg, wParam, lParam);  // Call old handler
         
         // Do your special draw stuff

         return(0);   // Return zero
     }

HDC hdc;
hdc = GetDCEx(hwnd, (HRGN)wParam, DCX_WINDOW|DCX_INTERSECTRGN);

HBITMAP hBmp;  // This needs to be held somewhere for life of dialog or global
HDC hMemDC;  // This is  the same it needs to be held somewhere for life of dialog or global

hBmp = (HBITMAP) LoadImage(0, "SomeName.Bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE); // Load bitmap file
hMemDC = CreateCompatibleDC(NULL);  // Create memory device context
if (hMemDC) SelectObject(hMemDC, hBmp); // Select the bitmap to any valid memory context

// Optional stuff you might want the loaded bitmap dimensions
BITMAP bm;
GetObject(hBmp, sizeof(bm), &bm); // Get object data
BmpWth = bm.bmWidth; // Get and hold bitmap width to some dialog life variable
BmpHt = bm.bmHeight; // Get and hold bitmap height to some dialog life variable

HDC hdc = GetDCEx(hwnd, (HRGN)wParam, DCX_WINDOW|DCX_INTERSECTRGN); // Get DC
BitBlt(hdc, ???, ???, BmpWth, BmpHt, hMemDC, 0, 0, SRCCOPY); // Transfer bitmap ... ??? are co-ords where to place 

DeleteObject(hBmp); // Release loaded bitmap
DeleteDC(hMemDC); // Release the memory context created above