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Standard library header <cfloat>

From cppreference.com
< cpp‎ | header

This header was originally in the C standard library as <float.h>.

This header is part of the type support library, in particular it's part of the C numeric limits interface.

[edit] Macros

FLT_RADIX
the radix (integer base) used by the representation of all three floating-point types
(macro constant)
DECIMAL_DIG
(C++11)
conversion from long double to decimal with at least DECIMAL_DIG digits and back to long double is the identity conversion. : this is the decimal precision required to serialize/deserialize a long double (see also std::numeric_limits::max_digits10)
(macro constant)
FLT_DECIMAL_DIGDBL_DECIMAL_DIGLDBL_DECIMAL_DIG
(C++17)
conversion from float/double/long double to decimal with at least FLT_DECIMAL_DIG/DBL_DECIMAL_DIG/LDBL_DECIMAL_DIG digits and back is the identity conversion. : this is the decimal precision required to serialize/deserialize a floating-point value (see also std::numeric_limits::max_digits10). Defined to at least 6, 10, and 10 respectively, or 9 for IEEE float and 17 for IEEE double.
(macro constant)
FLT_MINDBL_MINLDBL_MIN
minimum normalized positive value of float, double and long double respectively
(macro constant)
FLT_TRUE_MINDBL_TRUE_MINLDBL_TRUE_MIN
(C++17)
minimum positive value of float, double and long double respectively
(macro constant)
FLT_MAXDBL_MAXLDBL_MAX
maximum value of float, double and long double respectively
(macro constant)
FLT_EPSILONDBL_EPSILONLDBL_EPSILON
difference between 1.0 and the next representable value for float, double and long double respectively
(macro constant)
FLT_DIGDBL_DIGLDBL_DIG
number of decimal digits that are guaranteed to be preserved in text -> float/double/long double -> text roundtrip without change due to rounding or overflow (see std::numeric_limits::digits10 for explanation)
(macro constant)
FLT_MANT_DIGDBL_MANT_DIGLDBL_MANT_DIG
number of base FLT_RADIX digits that can be represented without losing precision for float, double and long double respectively
(macro constant)
FLT_MIN_EXPDBL_MIN_EXPLDBL_MIN_EXP
minimum negative integer such that FLT_RADIX raised by power one less than that integer is a normalized float, double and long double respectively
(macro constant)
FLT_MIN_10_EXPDBL_MIN_10_EXPLDBL_MIN_10_EXP
minimum negative integer such that 10 raised by power one less than that integer is a normalized float, double and long double respectively
(macro constant)
FLT_MAX_EXPDBL_MAX_EXPLDBL_MAX_EXP
maximum positive integer such that FLT_RADIX raised by power one more than that integer is a normalized float, double and long double respectively
(macro constant)
FLT_MAX_10_EXPDBL_MAX_10_EXPLDBL_MAX_10_EXP
maximum positive integer such that 10 raised by power one more than that integer is a normalized float, double and long double respectively
(macro constant)
default rounding mode of floating-point arithmetics
(macro constant)
specifies in what precision all arithmetic operations are done
(macro constant)
FLT_HAS_SUBNORMDBL_HAS_SUBNORMLDBL_HAS_SUBNORM
(C++17)
specifies whether the type supports subnormal (denormal) numbers: -1 indeterminable, 0 absent, 1 present
(macro constant)