The _lwrite function writes data to the specified file. This function is provided for compatibility with 16-bit versions of Windows. Win32-based applications should use the WriteFile function.
UINT _lwrite(
| HFILE hFile, | // handle to file | 
| LPCSTR lpBuffer, | // pointer to buffer for data to be written | 
| UINT uBytes | // number of bytes to write | 
| ); | 
If the function succeeds, the return value indicates the number of bytes actually written to the file.
If the function fails, the return value is HFILE_ERROR. To get extended error information, call GetLastError.
If you are attempting to write to a floppy drive that does not have a floppy disk, the system displays a message box prompting the user to retry the operation. To prevent the system from displaying this message box, call the SetErrorMode function with SEM_NOOPENFILEERRORBOX.