G++_QUADMATH
G++ Quadruple Real Precision

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.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages

Versions of the QUADMATH examples are available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version.

Related Data and Programs:

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.

Reference:

1. Brian Gough,
   An Introduction to GCC,
   Network Theory Ltd,
   ISBN: 0-9541617-9-3.
2. Arthur Griffith,
   GCC: The Complete Reference,
   McGrawHill,
   ISBN: 0-07-222405-3.
3. Richard Stallman,
   Using GCC: The Gnu Compiler Collection Reference,
   Free Software Foundation,
   ISBN: 1-882114-39-6.

Examples and Tests:

• g++_quadmath.cpp, a program that makes a simple test of the quadruple precision real arithmetic facility.
• g++_quadmath.sh, commands that compile and run the test;
• g++_quadmath_output.txt, the output file;

You can go up one level to the C++ source codes.