In my programe I need to replace _open and _wopen by windows api function, I think the function OpenFile should be the one.

Are their return values are same indeed, since _open/_wopen return int, while OpenFile return HFILE, and those enum type look confusing.

Can anyone help with it? At least where can I find useful information. Thank you very much

>>At least where can I find useful information
MSDN is the best source for win32 api functions. I don't like OpenFile() because it only does binary reads/writes, but is useful to serialize MFC objects with CArchive MFC class. Otherwise I much prefer standard c++ fstream. Just because you are writing a Windows program doesn't mean you can't use standard C++ classes and STL containers.