C++ :: Performing RegEx On Open File

I'm trying to open a file and perform a regex on it, then print the matches, but I'm not sure if I have it right. I think I need to remove the line -

Code:
[for ( std::vector<TCHAR>::iterator It = buffer.begin();It != buffer.end(); It++ )

since I've already copied the file into the buffer, but how do I search the buffer?

Code:
std::ifstream in(TempFullPath, std::ios::in|std::ios::binary);
if( in.fail() )
{
std::cout << "File does not exist or could not open file";
}

[Code]....