[Explanation] Real floating-point type, usually mapped to an extended precision floating-point number format. Actual properties unspecified. Unlike types float and double, it can be either 80-bit floating point format, the non-IEEE "double-double" or IEEE 754 quadruple-precision floating-point format if a higher precision format is provided, otherwise it is the same as double. See the article on long double for details. [Format Specifier] %Lf [Type] 
long double