How do I create std::ifstream from wchar_t* in C++?

Question

I want to check if a given file can be read. I am using following code snippet:

std::string fullPath("/test/text.txt");
std::ifstream stream(fullPath.c_str());
if (stream.good())
{
    //File can be read     
}

Above piece of code is working fine for me. My requirement changes a little where input in const wchar_t* instead of std::string. What changes do I need to do in order to make this piece of code work for me?