CreateFile, ReadFile, WriteFile

How do I use these functions for opening and reading/writing to files?


I have been trying to figure that out for a few hours, and I can't seem to get it to work.. :(


Thanks,
Dennis

Here are two great functions for loading and saving files using these API's.

Code:

---

BOOL SaveFile(HWND hEdit, LPSTR pszFileName)
{
  HANDLE hFile;
  BOOL bSuccess = FALSE;

  hFile = CreateFile(pszFileName, GENERIC_WRITE, NULL, NULL,
      CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
  if(hFile != INVALID_HANDLE_VALUE)
  {
      DWORD dwTextLength;
      dwTextLength = GetWindowTextLength(hEdit);
      if(dwTextLength > 0)// No need to bother if there's no text.
      {
        LPSTR pszText;
        pszText = (char*)GlobalAlloc(GPTR, dwTextLength + 1);
        if(pszText != NULL)
        {
            if(GetWindowText(hEdit, pszText, dwTextLength + 1))
            {
              DWORD dwWritten;
              if(WriteFile(hFile, pszText, dwTextLength, &dwWritten, NULL))
                  bSuccess = TRUE;
            }
            GlobalFree(pszText);
        }
      }
      CloseHandle(hFile);
  }
  return bSuccess;
}

BOOL LoadFile(HWND hEdit, LPSTR pszFileName)
{
  HANDLE hFile;
  BOOL bSuccess = FALSE;

  hFile = CreateFile(pszFileName, GENERIC_READ, FILE_SHARE_READ, NULL,
      OPEN_EXISTING, NULL, NULL);
  if(hFile != INVALID_HANDLE_VALUE)
  {
      DWORD dwFileSize;
      dwFileSize = GetFileSize(hFile, NULL);
      if(dwFileSize != 0xFFFFFFFF)
      {
        LPSTR pszFileText;
        pszFileText = (char*)GlobalAlloc(GPTR, dwFileSize + 1);
        if(pszFileText != NULL)
        {
            DWORD dwRead;
            if(ReadFile(hFile, pszFileText, dwFileSize, &dwRead, NULL))
            {
              pszFileText[dwFileSize] = 0; // Null terminator
              if(SetWindowText(hEdit, pszFileText))
                  bSuccess = TRUE; // It worked!
            }
            GlobalFree(pszFileText);
        }
      }
      CloseHandle(hFile);
  }
  return bSuccess;
}

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Thanks a lot.. just what I needed :)