Long Double

Previous 16-bit versions of Microsoft C/C++ and Microsoft Visual C++ supported the long double, 80-bit precision data type. In Win32 programming, however, the long double data type maps to the double, 64-bit precision data type. The Microsoft run-time library provides longdouble versions of the math functions only for backward compatibility. The longdouble function prototypes are identical to the prototypes for their double counterparts, except that the longdouble data type replaces the double data type. The longdouble versions of these functions should not be used in new code.

Double Functions and Their Long Double Counterparts