Self implemented IsInteger() function in C++

IsInteger.h

#ifndef IsInteger
#define IsInteger

// Note: Here, RealNumberType should be convertible to int
// and the value contained in RealNumberType should not be greater than
// max value of int

//Maybe IntegerType should only be take as template arguement (seems necessary)
//Original type of arguement might be found using typeinfo or something...(Not sure, check)
namespace GS{

template <typename RealNumberType>
bool isInteger(RealNumberType n)
{
	int i = (int)n;
	return ((RealNumberType)i==n);
}

}
#endif