Good Old fopen() does the trick
FILE *fp;
if ((fp = fopen((LPCTSTR)fName, "r")) == NULL)
{
}
else
{
fclose(fp);
}
(Updated)
If you're going to downvote the answer, at least have the courtesy to say why. Does "fopen()" not work? Of course it does, on all platforms, C and C++. The other solution points to a link that outlines several ways but require 3rd party (boost) or use functions that have different names for Windows and Linux (_access(), access()) which isn't "code transparent", meaning that you have to conditionalize the code for platform. If you're going to do that, you might as well use the platform specific calls and give up the idea of platform agnostic calls.
I'm not saying this is the "ideal" or "only" answer, I'm saying it answered the OPs question as posed and is not a "bad answer", maybe it's just one you don't like, but not wrong.