How to check if file exists in C++ in a portable way?

Question

Currently I use this code to check if file exists on Windows and POSIX-compatible OSes (Linux, Android, MacOS, iOS, BlackBerry 10):

bool FileExist( const std::string& Name )
{
#ifdef OS_WINDOWS
    struct _stat buf;
    int Result = _stat( Name.c_str(), &buf );
#else
    struct stat buf;
    int Result = stat( Name.c_str(), &buf );
#endif
    return Result == 0;
}

Questions:

1. Does this code have any pitfalls? (maybe an OS where it cannot be compiled)

2. Is it possible to do it in a truly portable way using only C/C++ standard library?

3. How to improve it? Looking for canonical example.

Answer 1

I perosnally like to just try to open the file:

bool FileExist( const std::string& Name )
{
     std::ifstream f(name.c_str());  // New enough C++ library will accept just name
     return f.is_open();
}

should work on anything that has files [not required by the C++ standard] and since it's using C++ std::string, I don't see why std::ifstream should be a problem.