Why I get the following warning for the following code :)

Code:

_stprintf(m_szFileNamePath,_T("%s"),strFileName);

warning C4996: '_swprintf': swprintf has been changed to conform with the ISO C standard, adding an extra character count parameter. To use traditional Microsoft swprintf, set _CRT_NON_CONFORMING_SWPRINTFS.

I know _strprintf is a macro which if _UNICODE is defined will evaluate to _swprintf else it will be sprintf.

Now what is this _swprintf. There is a function swprintf, but why is _stprintf evaluating to _swprintf instead of swprintf.

What is the difference b/w the _xxx and xxx functions?

EDIT:

Okay there are two definitions for the UNICODE version of _stprintf, which one is included?

The one in tchar.h or strsafe.h?