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

[Vlatko]

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

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;
}

Thanks a lot.. just what I needed :)