<cfloat> support

The following macros analogous to those from <cfloat> for the decimal floating point types:

#include <boost/decimal/cfloat.hpp>


// Number of digits in the coefficient
#define BOOST_DECIMAL_DEC32_MANT_DIG  std::numeric_limits<boost::decimal::decimal32_t>:digits10
#define BOOST_DECIMAL_DEC64_MANT_DIG  std::numeric_limits<boost::decimal::decimal64_t>:digits10
#define BOOST_DECIMAL_DEC128_MANT_DIG std::numeric_limits<boost::decimal::decimal128_t>:digits10

// Minimum exponent
#define BOOST_DECIMAL_DEC32_MIN_EXP  std::numeric_limits<boost::decimal::decimal32_t>:min_exponent
#define BOOST_DECIMAL_DEC64_MIN_EXP  std::numeric_limits<boost::decimal::decimal64_t>:min_exponent
#define BOOST_DECIMAL_DEC128_MIN_EXP std::numeric_limits<boost::decimal::decimal128_t>:min_exponent

// Maximum exponent
#define BOOST_DECIMAL_DEC32_MAX_EXP  std::numeric_limits<boost::decimal::decimal32_t>:max_exponent
#define BOOST_DECIMAL_DEC64_MAX_EXP  std::numeric_limits<boost::decimal::decimal64_t>:max_exponent
#define BOOST_DECIMAL_DEC128_MAX_EXP std::numeric_limits<boost::decimal::decimal128_t>:max_exponent

// Maximum Finite Value
#define BOOST_DECIMAL_DEC32_MAX  std::numeric_limits<boost::decimal::decimal32_t>::max()
#define BOOST_DECIMAL_DEC64_MAX  std::numeric_limits<boost::decimal::decimal64_t>::max()
#define BOOST_DECIMAL_DEC128_MAX std::numeric_limits<boost::decimal::decimal128_t>::max()

// Minimum positive normal vlaue
#define BOOST_DECIMAL_DEC32_MIN std::numeric_limits<boost::decimal::decimal32_t>::min()
#define BOOST_DECIMAL_DEC64_MIN   std::numeric_limits<boost::decimal::decimal64_t>::min()
#define BOOST_DECIMAL_DEC128_MIN std::numeric_limits<boost::decimal::decimal128_t>::min()

// Minimum positive sub-normal value
#define BOOST_DECIMAL_DEC32_MAX  std::numeric_limits<boost::decimal::decimal32_t>::denorm_min()
#define BOOST_DECIMAL_DEC64_MAX  std::numeric_limits<boost::decimal::decimal64_t>::denorm_min()
#define BOOST_DECIMAL_DEC128_MAX std::numeric_limits<boost::decimal::decimal128_t>::denorm_min()

Additionally BOOST_DECIMAL_DEC_EVAL_METHOD is similar to FLT_EVAL_METHOD: https://en.cppreference.com/w/cpp/types/climits/FLT_EVAL_METHOD

The valid values are:

Value

Description

0

All operations evaluated in the range and precision of the native type

1

All decimal32_t (or decimal_fast32_t) operations are evaluated with the precision and range of decimal64_t internally, and returned as decimal64_t

2

All decimal32_t and decimal64_t (or fast equivalents) operations are evaluated with the precision and range of decimal128_t internally, and returned as the original type.

To use the functionality you must #define BOOST_DECIMAL_DEC_EVAL_METHOD to the value you want before you #include <boost/decimal.hpp>.

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