G++_QUADMATH is a C++ program which illustrates the use of quadruple real precision arithmetic with the Gnu G++ compiler for C++.
Every C++ compiler offers a single precision real datatype called float as well as a double precision real data type called double.
Such variables can be declared with statements such as:
float w;
double x;
On some systems, the G++ compiler provides a real data type stored in 80 bytes, and declared as a __float80, and on some systems, a real data type stored in 128 bytes, declared as a __float128. Variable declarations would be
__float80 y;
__float128 z;
The Macintosh OSX system I have access to seems to have the __float80 option, but not the __float128 option.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
Versions of the QUADMATH examples are available in a C version and a C++ version and a FORTRAN90 version.
G++_INTRINSICS, a C++ program which illustrates the use of intrinsic functions provided by the Gnu G++ compiler for C++.
G95_QUADMATH, a FORTRAN90 program which illustrates the use of quadruple precision real arithmetic provided on some systems by the G95 compiler for FORTRAN.
You can go up one level to the C++ source codes.